71.

Lobar pneumonia
72. Interstitial pneumonia
73. Fibroproductive pleuritis (pleurisy)
74. Squamous cell carcinoma of the lungs
75. Small cell carcinoma of the lungs
76. Extramedullary hematopoiesis in the liver
77. Chronic lymphocytic leukemia in the liver
78. Chronic myeloid leukemia in the liver
79. Small lymphocytic lymphoma in the lymph node
80. Plasma cell myeloma
 71. Lobar pneumonia
• lobar (croupous) pneumonia is an acute bacterial infection affecting the entire lung
lobe or a large part of it
• more than 90% of cases are caused by Streptococcus pneumoniae
• the infection is mostly community-acquired
• clinical manifestations: chills, fever, pleuritic chest pain, dyspnea, tachypnea, and
tachycardia, cough with expectoration of mucopurulent or blood-colored sputum, and
leukocytosis with an increased proportion of neutrophilic leukocytes in the blood
• in untreated cases, 4 classical stages from the morphological point of view
• with timely antibiotic treatment, clinical state improves within 48-72 hours, and these
stages may not be present
• complications of untreated pneumonia: organization of exudate with resulting
pulmonary fibrosis, pleural effusion or empyema, lung abscess and spread of infection
(metastatic abscesses in the brain, spleen, kidneys, bacterial endocarditis, purulent
pericarditis, meningitis and arthritis)
 MACROSCOPIC IMAGE
• 1. stage of congestion (first 1-2 days): represents an early response to bacterial
infection. The affected lobe is enlarged, congested, heavy, dark red on the surface
and cut section, and a blood-colored, frothy fluid leaks from the cut surface.
• 2. stage of red hepatization (2nd-4th day): the lung lobe has an appearance and
consistency similar to liver tissue (thus hepatization), it is airless, firm, red and
dry on cut section. At this stage, pneumonia is accompanied by fibrinous pleurisy.
• 3. stage of gray hepatization (4th-8th day): the cut surface is grey-brown to grey
in color, dry, with the consistency of liver.
• 4. stage of resolution (untreated pneumonia from the 8th day, treated
pneumonia from the 3rd day, completed in 1-3 weeks): progressive enzymatic
digestion of the exudate, which is subsequently resorbed, phagocytosed or
expectorated, takes place. Resolution of pleurisy may also occur, but more often
it heals by organization and the pleural surface thickens.
MACROSCOPIC IMAGE
 MICROSCOPIC IMAGE
• 1. stage of congestion: noticeable dilation and hyperemia of the capillaries in the
alveolar septa, the alveoli are filled with edema fluid containing numerous bacteria
and rare neutrophils.
• 2. stage of red hepatization: the cellular component of inflammation is dominant. In
the alveoli, numerous erythrocytes, responsible for the macroscopically red color,
neutrophils containing phagocytosed bacteria, and fibrin fibers, are found.
• 3. stage of gray hepatization: characterized by the presence of numerous fibrin
fibers, giving the lobe grey color, and the disintegration of erythrocytes and
neutrophils, which are less numerous. Macrophages also appear in the exudate,
bacteria decrease in number.
• 4. stage of resolution: granular fluid in the alveoli is observed as a result of
enzymatic decomposition of exudate. This content gradually disappears and is
replaced by air.
 72. Interstitial pneumonia
• interstitial (primary atypical) pneumonia is characterized by involvement of the pulmonary
interstitium, i.e. walls of the alveoli, without a significant alveolar exudate characteristic of
typical bacterial pneumonia
• caused by infection with atypical pathogens, mainly viruses (respiratory syncytial virus,
influenza and parainfluenza viruses, coxsackie, adenoviruses, rhinoviruses and
cytomegalovirus), but also Mycoplasma pneumoniae, more rarely Chlamydia psittaci and
Coxiella (Q-fever)
• in most of these infections, the involvement is limited to the upper respiratory tract, but
factors such as malnutrition, alcoholism and chronic diseases may enable spread of the
infection to the pulmonary interstitium
• clinical manifestations: fever, cough, tachypnea and dyspnea, rarely respiratory failure;
physical findings are usually poor
• morphological picture is similar in all cases - most cases resolve completely, in severe cases
there is injury to the alveoli and development of interstitial fibrosis
• main complication is secondary bacterial superinfection, which often has a more severe course
 MACROSCOPIC IMAGE
• patchy distribution of inflammation, but
in more severe infections, a more
extensive involvement of the entire
lobe/lobes of one or both lungs may be
present
• lungs are heavier due to congestion, the
affected areas are reddish-blue, and a
smaller amount of foamy or blood-
stained fluid flows from the cut surface
• pleuritis and pleural effusion are
uncommon
 MICROSCOPIC IMAGE
• inflammatory reaction in the alveolar walls - septa are dilated due to vascular
congestion and edema and contain a mononuclear inflammatory infiltrate
consisting of lymphocytes, macrophages, and isolated plasma cells; in acute cases,
neutrophils may also be present
• alveoli are either filled with air or contain eosinophilic proteinaceous material and
occasional inflammatory cells
• some cases are associated with necrosis of the alveolar and bronchiolar
epithelium, with a mononuclear infiltrate in the lumen and wall of the bronchioles
(necrotizing bronchiolitis)
• if patient develops alveolar damage linked to the acute respiratory distress
syndrome (ARDS), the alveolar walls are lined from the inside with pink hyaline
membranes
 73. Fibroproductive pleuritis (pleurisy)
• pleuritis, or inflammation of the pleura, can be infectious or non-infectious
• pleuritis most often arises as a secondary complication of another underlying disease affecting the
lungs
• it occurs mainly in pulmonary tuberculosis, pneumonia, pulmonary infarction, lung abscess and
bronchiectasis
• it can also be caused by systemic diseases of the connective tissue such as rheumatoid arthritis and SLE,
uremia, metastatic involvement of the pleura, radiotherapy and systemic infections
• in the acute stage, it is manifested by sharp pain in the chest during inspiration
• exudate accumulates in the pleural cavity - according to its nature and etiology, serous, fibrinous,
serofibrinous, purulent and hemorrhagic pleuritis are distinguished
• accumulation of greater volume of inflammatory fluid is also associated with lung collapse on the
affected side and respiratory distress
• in serous pleurisy, the exudate is completely resorbed during healing and resolution occurs
• if the exudate also contains a higher amount of fibrin (e.g. in fibrinous and purulent pleuritis), the
inflammation is healed by the organization of fibrin with the resulting fibrous thickening of the pleura,
and fibrous adhesions between both layers of the pleura = fibroproductive pleuritis
MACROSCOPIC IMAGE
• fibrous adhesions that are formed in fibroproductive pleuritis can
sometimes cause complete obliteration of the pleural cavity (pleuritis
fibrosa) or form a continuous thick fibrous covering on the surface of
the lung (pleuritis callosa), thus limiting lung expansion
• adhesions can also later calcify and transform into a hard shell
(pleuritis petrosa/calcificans) or metaplastic bone can form within the
adhesions (pleuritis ossificans)
MACROSCOPIC IMAGE
MICROSCOPIC IMAGE
• specimen contains visceral pleura and subpleural lung tissue
• the exudate that heals by organization is first replaced by granulation
tissue and later by fibrous tissue
• fibroblasts in the granulation tissue produce collagen, thereby
converting the granulation tissue into fibrous connective tissue, which
is initially more cellular and contains a relatively high number of
vessels and later transforms into a hyalinized fibrous tissue without
elastic fibers
 74. Squamous cell carcinoma of the lungs
• squamous cell carcinoma not otherwise specified (SCC NOS) is currently the
2nd most common histological type of lung cancer after adenocarcinoma
• it is preceded by squamous metaplasia and dysplasia of the bronchial
epithelium
• accounts for about 20% of lung cancer cases
• lung cancer is the most common cause of cancer-related deaths worldwide
• more often affects men, the highest incidence is in the 5th and 6th decades of
life
• in most cases, it is related to tobacco smoking; other etiological factors include
genetic predisposition, exposure to radon, asbestos, air pollution, chronic lung
disease, etc.
 74. Squamous cell carcinoma of the lungs
• clinical manifestations: hemoptysis, cough, dyspnea, pneumonia, chest pain,
weight loss, paraneoplastic manifestations, Horner's syndrome in case of
involvement of sympathetic nervous system, and others
• it metastasizes to lymph nodes, adrenal glands, liver, bones and brain
• almost all malignant lung tumors are carcinomas = they are of epithelial origin,
and arise from the epithelium of the bronchi, bronchioles or alveoli
• the following four histological types are most common: adenocarcinoma,
squamous cell carcinoma, small cell carcinoma and large cell carcinoma
• the diagnosis is based on histopathological features and growth pattern of
tumours as well as immunohistochemical examination and genetic profile of the
tumour
• an accurate diagnosis of the histological type is important in terms of treatment
and prognosis
MACROSCOPIC IMAGE
• SCC of the lungs usually grows from the main or lobar bronchus =
centrally (2/3 of cases), in 1/3 of cases grows peripherally
• usually characterized by endobronchial exophytic growth, causing
obstruction of the bronchial lumen, often with atelectasis of the
lung parenchyma beyond the site of obstruction and pneumonia due
to secondary fungal or bacterial infection
• tumour can also grow through the wall of the bronchus into
peribronchial structures
• usually white, light brown or grey on the cut section; focal areas of
bleeding and necrosis occur in larger tumors, which can lead to the
tumour cavitation
MACROSCOPIC
IMAGE
 MICROSCOPIC IMAGE
• SCC of the lungs has 3 histological subtypes: keratinizing, non-
keratinizing, and basaloid
• morphologically, it is characterized by the presence of intercellular
bridges and/or keratinization
• in the case of non-keratinizing and basaloid tumours, positivity of
immunohistochemical markers of squamous differentiation is required to
establish the diagnosis
• keratinization can take the form of keratin pearls, or only individual cells
with strongly eosinophilic cytoplasm are keratinized
• as in other locations, in pulmonary SCCs, well/moderately/poorly
differentiated and undifferentiated SCCs must be distinguished
 75. Small cell carcinoma of the lungs
• from the clinical and therapeutic point of view, lung cancers are divided into:
1. small cell carcinomas,
2. non-small cell carcinomas (which include adenocarcinomas, squamous cell
and large cell carcinomas),
3. combined, mixed tumors
• in small cell carcinoma, MTS are usually already present at the time of diagnosis,
and therefore its treatment consists of chemotherapy and/or radiotherapy, while
the treatment of non-small cell carcinomas is primarily surgical
• small cell carcinoma accounts for about 15% of lung carcinomas
• occurs primarily in heavy smokers, more often in men, with a peak incidence in the
7th decade of life
• highly malignant, poorly differentiated neuroendocrine tumor
75. Small cell carcinoma of the lungs
• it is assumed that it can arise from any epithelial cells of the lungs - from
basal cells, neuroendocrine cells or totipotent epithelial cells
• metastasizes within the lungs and to the liver, bones, brain, and adrenal
gland
• paraneoplastic manifestations are present more often than in other
histological types of lung cancer
• they result from the ectopic production of hormones, e.g. ACTH
(manifesting as Cushing's syndrome), and ADH/antidiuretic hormone
(leading to hyponatremia), or are immunologically mediated (peripheral
neuropathy, Lambert-Eaton syndrome)
• 5-year survival of patients with metastatic disease is approximately 2%
 MACROSCOPIC IMAGE
• usually occurs in the central region
of the lungs
• a large, unresectable mass in the
vicinity of the lung hilum, which can
cause bronchus compression, and
hilar lymph nodes are often affected
as well
• rarely, in about 5% of cases, a
circumscribed nodule on the
periphery of the lung
• yellow-brown on the cross-section
 MICROSCOPIC IMAGE
• composed of small, round, oval, or spindle-shaped cells with scant cytoplasm
and indistinct cell borders
• the size of tumour cells is usually less than the diameter of 3 small lymphocytes
• cells are densely packed and often arranged in sheets, exceptionally they have an
organoid arrangement
• extensive necrosis and numerous mitoses (average of 60 mitoses per 2 mm2) are
common in the tumor
• nuclear chromatin is finely granular, nucleoli are either absent or inconspicuous
• pleomorphic giant cells may also be present, but they must not exceed 10% of all
tumour cells
• immunohistochemically positive for neuroendocrine markers
• combined small cell carcinoma also contains a component of another, non-small
cell carcinoma
 76. Extramedullary hematopoiesis in the liver
• term extramedullary hematopoiesis (EH) refers to hematopoiesis that takes place in a different location than
the bone marrow
• physiological or pathological
• in the fetal period, before the maturation of the bone marrow, hematopoiesis occurs physiologically in the yolk
sac, liver, spleen and other places
• after reaching the maturity of the bone marrow in the perinatal period, hematopoiesis moves there, thus,
during childhood and adulthood, the main site of hematopoiesis is the bone marrow
• EH is therefore observed mainly in premature infants (physiological) and in adulthood in certain conditions
associated with the failure of normal blood formation in the bone marrow (pathological), when the
hematopoietic activity of the liver and spleen can be restored
• insufficient/inefficient hematopoiesis in the bone marrow associated with EH is caused by hematological
diseases such as myeloproliferative neoplasms (e.g. primary myelofibrosis), leukemias, lymphomas,
hemolytic anemias (sickle cell anemia, hereditary spherocytosis, thalassemia), idiopathic thrombocytopenic
purpura, etc.
• EH can also occur as a result of bone marrow irradiation, presence of extensive bone metastases, hypoxia or
as part of the immune response to pathogens
• in addition to the liver and spleen, EH can also occur in the lymph nodes, heart, lungs, kidneys, adrenal glands,
prostate, uterus, etc.
Hematopoiesis
MACROSCOPIC IMAGE
• liver is macroscopically diffusely enlarged (hepatomegaly), rarely with
one or more focal masses that may imitate metastases
 MICROSCOPIC IMAGE
• liver parenchyma is hypercellular
• extramedullary hematopoiesis takes place mainly in the sinusoids of the liver, in later stages
also in the periportal areas, which are dilated and contain groups of precursor and mature
blood cells
• the most represented are erythroid precursors, mainly normoblasts (erythroblasts), which
have round, hyperchromatic nuclei and a narrow rim of cytoplasm - small cells with an
appearance similar to lymphocytes
• sinusoids also contain myeloid precursors, sized between normoblasts and megakaryocytes,
with oval to variably indented nuclei depending on the stage, and blue cytoplasm
• also mature granulocytes and megakaryocytes (recognizable platelet precursors), which are
the largest cells of hematopoiesis, with a large lobulated nucleus and azurophilic cytoplasm
• dilation of the sinusoids leads to pressure atrophy of the surrounding hepatocytes
• in case of prolonged persistence of extramedullary hematopoiesis, fibrosis of the liver develops
• iron pigment may be present in Kupffer cells and hepatocytes
 77. Chronic lymphocytic leukemia in the liver
• chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) belongs to lymphoid
neoplasms, that originate in cells of the lymphoid hematopoietic series (B- and T-lymphocytes,
plasma cells, NK-cells)
• at the beginning, the disease can manifest itself as leukemia (primarily affecting the bone
marrow and blood) or lymphoma (primarily affecting the lymphoid tissue)
• later with the infiltration of other organs, the border between these two forms is lost
• although CLL and SLL are considered one disease, in CLL the number of monoclonal B-
lymphocytes in the peripheral blood has to be ≥ 5x109/l (peripheral lymphocytosis)
• according to prognosis and biological course, leukemias are divided into acute and chronic, and
at the same time they are classified according to the hematopoietic series from which they
originate as myeloid or lymphoid
• CLL is characterized by neoplastic proliferation of monomorphic, small, mature B-lymphocytes
• in Western countries, it is the most common type of leukemia in adults
• most cases occur around the age of 70 and it is 1,5-2 times more common in men
 77. Chronic lymphocytic leukemia in the liver
• CLL is most commonly diagnosed in asymptomatic patients on the basis of routine
hematological examination and usually has an indolent course
• some patients present with nonspecific clinical manifestations such as anemia
(weakness, fatigue, dyspnea), thrombocytopenia (bleeding disorders),
hepatosplenomegaly, lymphadenopathy (enlarged lymph nodes) and susceptibility to
infections due to hypogammaglobulinemia
• the aforementioned manifestations result from the suppression of normal
hematopoiesis in the bone marrow and infiltration of other organs
• bone marrow, peripheral blood, lymph nodes, spleen are typically affected, less often
there is infiltration of the liver, skin, gastrointestinal mucosa, kidneys and CNS
• prognosis is variable and depends on the associated genetic abnormalities
• approximately in 2-8% of patients, CLL will transform into aggressive diffuse large B-
cell lymphoma as a result of the acquisition of additional mutations
MACROSCOPIC IMAGE
• liver is enlarged due to infiltration by leukemic cells (hepatomegaly)
MICROSCOPIC IMAGE
• conspicuous infiltrates of small, uniform lymphocytes, similar to
normal lymphocytes, in periportal areas
• tumour cells have round, hyperchromatic nuclei with clumped
chromatin and scant cytoplasm
• mitotic activity of the cells is usually low
• in addition to these mature cells, prolymphocytes (small to medium-
sized cells with visible nucleoli) and paraimmunoblasts (larger cells
with irregular nuclear contours, scattered chromatin, and bulkier
cytoplasm) may also be found in small numbers
• sinusoids are inconspicuous, with a minimal number of cells
 78. Chronic myeloid leukemia in the liver
• chronic myeloid leukemia (CML), BCR-ABL1-positive, belongs to myeloproliferative neoplasms of the bone marrow,
characterized by clonal proliferation of cells of the myeloid hematopoietic line (erythrocytes, platelets,
granulocytes and monocytes), in this disease primarily of granulocytes = myeloproliferative neoplasm in which
granulocytes are the major proliferative component
• it arises from an abnormal pluripotent hematopoietic stem cell with a characteristic translocation of chromosomes
9 and 22, referred to as the Philadelphia (Ph) chromosome
• chromosomal translocation t(9;22)(q34.1;q11.2) resulting in the formation of the Philadelphia (Ph) chromosome
contains the BCR-ABL1 fusion gene
• the translocation results in the formation of BCR-ABL1 fusion gene with persistent tyrosine-kinase activation of
oncogenic signaling pathways
• the presence of the gene sequence known as BCR-ABL1 confirms the diagnosis of CML and a form of acute
lymphoblastic lymphoma (ALL), specifically a type of B-lymphoblastic leukemia/lymphoma
• CML can occur at any age, but the peak incidence is in 5-7th decade
• exposure to radiation is the main risk factor
• about half of the cases are asymptomatic, incidentally diagnosed on the basis of leukocytosis in peripheral blood
(12-1000 x 109/l with a predominance of neutrophil granulocytes in various stages of maturation, especially
myelocytes and segmented neutrophils)
• in the chronic phase, the proportion of immature blasts in the blood is <2% and in the bone marrow <5%
• basophilia and eosinophilia are common, the number of platelets is normal or increased
 78. Chronic myeloid leukemia in the liver
• bone marrow is hypercellular, with conspicuous proliferation of granulocytes
• leukemic neutrophils have reduced neutrophil alkaline phosphatase activity
• the most common manifestations include fatigue, weight loss, night sweats, anemia and
splenomegaly
• within 3-5 years of diagnosis, untreated CML will transform from an initial chronic phase through
an accelerated phase, which may also be absent, to a blast crisis with features of acute leukemia
(≥ 20% immature blasts in the blood or bone marrow) and an unfavorable prognosis
• when treated with tyrosine kinase inhibitors, the 10-year survival rate is 80-90%
• diagnosis consists of the examination of peripheral blood and the detection of the Ph
chromosome and/or BCR-ABL1 gene by cytogenetic/molecular techniques
• in the chronic phase, in addition to the involvement of the bone marrow and blood, there is also
infiltration of the liver and spleen (hepatosplenomegaly)
• with the transition to blast crisis, there is also infiltration of lymph nodes, skin and soft tissues
• there are also other, BCR-ABL1-negative, CMLs
MACROSCOPIC IMAGE
• liver is macroscopically enlarged due to the infiltration by leukemic
cells (hepatomegaly)
MICROSCOPIC IMAGE
• hepatic sinusoids are dilated and hypercellular
• they contain an infiltrate of neoplastic granulocytes in different
stages of maturation
• the most represented are myelocytes with an oval or kidney-shaped
nucleus with granular chromatin, blue cytoplasm with azurophilic
granules, and mature segmented neutrophils
• immature blasts are less numerous
• small numbers of eosinophils, basophils and megakaryocytes may
also be present in the infiltrate
• tumor cells can also infiltrate periportal areas to a lesser extent
79. Small lymphocytic lymphoma in the lymph node
• chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) belongs to
the group of neoplasms arising from the monoclonal proliferation of either
precursor cells of the lymphoid lineage or mature B-, T- or NK-cells
• although CLL and SLL are considered a single disease, SLL is characterized by
<5x109/L monoclonal B-cells in peripheral blood and evidence of lymph node
(LN), spleen, or other extramedullary site involvement
• lymphomas represent a group of malignant neoplasms affecting primarily the
lymphoid tissue
• they may be associated with characteristic genetic abnormalities, on the basis of
which they are classified into different subtypes
• they are divided into Hodgkin's (HL) and non-Hodgkin's (NHL) lymphomas
• HL differ from NHL by specific pathological features (presence of Hodgkin and
Reed-Sternberg cells) and treatment method
79. Small lymphocytic lymphoma in the lymph node
• diagnosis is based on LN biopsy
• HL and 2/3 of NHL are manifested by painless enlargement of the LN
• in the remaining third of NHL, the manifestations result from extranodal involvement
(e.g. skin, stomach or CNS)
• neoplasms arising from mature B-cells constitute > 90% of all lymphoid neoplasms,
with a median occurrence in 6-7th decade of life
• one of the main risk factors is immunodeficiency or autoimmune disease, some types of
lymphoma are associated with HIV, EBV, HHV8, HTLV-1 or Helicobacter pylori infection
• the most common types of NHL are follicular lymphoma and diffuse large B-cell
lymphoma; SLL represents 7% of NHL
• Burkitt's lymphoma is endemic in equatorial Africa, where it is the most common
childhood malignancy
• lymphoid neoplasms arising from precursor cells (e.g. B-lymphoblastic
leukemia/lymphoma, T-lymphoblastic leukemia/lymphoma) are also primarily diseases
of children
 MACROSCOPIC IMAGE
• the affected lymph node is enlarged
• homogenous, fleshy appearance on the cross-section, grey-white in color
• extranodal involvement may be in the form of a discrete tumorous mass or leads
to a diffuse enlargement of the organ

Source:
https://www.gponline.com/haematology-
chronic- Paraaortic lymph nodes
leukaemia/haematology/haematology/article/ Source: Source:
1055828 https://www.tandfonline.com/doi/abs/10.10 https://www.pathologyoutlines.com/topic/ly
80/10428190601137336?journalCode=ilal20 mphomaCLL.html
 MICROSCOPIC IMAGE
• normal architecture of the lymph node (cortex with lymphatic follicles,
and medulla) is replaced by a diffuse infiltration of uniform small, round
cells, similar to normal lymphocytes
• tumor cells have dark, round nuclei, occasionally with a small nucleolus,
and a small amount of cytoplasm
• the cells can infiltrate the capsule of the lymph node and spread into the
surrounding soft tissue (extranodal extension)
• scattered paler proliferative centers consisting of small lymphocytes,
prolymphocytes and paraimmunoblasts can also be found in the infiltrate
LN – normal histology
 80. Plasma cell myeloma
• plasma cell myeloma (multiple myeloma - MM) represents 10-15% of
hematological neoplasms and belongs to lymphoid neoplasms of plasma cells
• these are characterized by the proliferation of one clone of cells that produce a
monoclonal immunoglobulin (Ig), called the M protein, most often composed of
IgG, IgA or only light chains
• about 1% is non-secretory myeloma
• MM represents a multifocal neoplastic proliferation of plasma cells in the bone
marrow, usually associated with osseous and extraosseous manifestations due to
tumor infiltration, and presence of M protein in serum and/or urine
• clinical presentation is variable, from asymptomatic plasma cell myeloma to
highly aggressive disease, with survival ranging from < 6 months to > 10 years
• plasmacytosis is common in the blood
 80. Plasma cell myeloma
• as a result of osteoclast activation, hypercalcemia, bone pain, and bone
osteolytic lesions associated with pathological fractures are present
• other manifestations include infections due to the suppression of normal Ig
synthesis, anemia, bleeding disorders, AL amyloidosis and renal insufficiency
(myeloma kidney), caused by the passage of light chains (Bence-Jones protein)
into the tubular lumina
• 90% of cases occur in the age > 50 years
• term plasmacytoma is used in the case of a solitary, localized tumor without the
organ damage typical of MM
• it takes the form of a solitary plasmacytoma of the bone or an extraosseous
(extramedullary) plasmacytoma, that arises in a location other than bone, e.g. in
the mucosa of the respiratory system, GIT, lymph nodes, urinary bladder, breast,
etc.
 MACROSCOPIC IMAGE
• bone marrow involvement is typically multifocal, with the formation of tumorous masses
in several bones, often associated with osteolysis
• vertebrae, ribs, skull, shoulders, pelvis and long bones are most often affected
• macroscopically, these osteolytic lesions are filled with soft, gelatinous, reddish tissue
• in advanced stages, extramedullary involvement is also present
Gross photo shows a resected femoral
head involved by plasmacytoma. Lesion is
well demarcated from surrounding
cancellous bone. Tumor is soft and
hemorrhagic, & adjacent cancellous bone
is free of tumor.

Lateral radiograph of skull shows multiple

Source: https://basicmedicalkey.com/plasmacytomamyeloma/
 MICROSCOPIC IMAGE
• bone marrow replacement by the neoplastic plasma cells, which usually
represent at least 30% of the bone marrow volume
• they can be scattered, form small clusters, foci or diffuse infiltrates
• normal hematopoiesis is often preserved, but in diffuse involvement it is
significantly reduced
• the appearance of myeloma cells is variable, from immature and pleomorphic
cells with an increased nucleo-cytoplasmic ratio and prominent nucleoli, to
mature forms resembling normal plasma cells
• mature forms are oval, have voluminous basophilic cytoplasm with perinuclear
clearing (hof, halo) and a round, eccentrically located nucleus with chromatin
arranged in a radial, spoke-wheel pattern, usually without visible nucleoli; the
cytoplasm contains round Russell bodies, formed by synthesized Ig
• present bony trabeculae can be resorbed to a large extent
Russel bodies