Pseudosarcoma
- 2. • Soft tissue is defined ascomplex of nonepithelial extra skeletal structure ofbody exclusive of supportive tissue of various organs and the hematopoietic/ lymphoid tissue.
- 3. • It is composed of fibrous tissue, adipose tissue, skeletal muscle, blood and lymph vesselsand peripheral nerve. • Most of the soft tissue derived from mesoderm with neuroectodermal contribution corresponding to peripheral nerve.
- 5. Pseudosarcoma • One of the most common and important pitfalls in soft tissue pathology are the so-called pseudosarcomas. These lesions are nonneoplastic; however, their rapid growth, hypercellularity, cytologic atypia, and mitotic activity makes them prone to be misinterpreted as sarcoma. • Most of these lesions rarely recur following simple excision; therefore, their accurate recognition helps prevent excessive therapy.
- 6. Pseudosarcoma • Reactive pseudoarcomatous proliferations are non neoplastic lesions that either develop in response to trauma or idiopathic. • Clinically they are alarming because they develop suddenly and grow rapidly.
- 7. Example include • Reactive fibroblastic and myofibroblastic proliferation resembling soft tissue sarcoma • Reactive endothelial proliferation resembling soft tissue sarcoma • Mass forming inflammatory histocytic and infective lesion resembling soft tissue sarcoma • Benign connective tissue tumors resembling soft tissue sarcoma
- 8. Reactive fibroblastic and myofibroblastic proliferation resembling soft tissue sarcoma • Nodular fascitis • Proliferative fasciitis and proliferative myositis • Myositisossificans
- 9. Nodular fascitis • Most commonpseudosarcoma • Most often occur in adults and volar aspect of forearm. • Gross– several centimeters in diameter , nodular configuration, poorly definedmargins.
- 10. Sites of involvement Nodular fasciitis is usually subcutaneous, occasional are intramuscular. Dermal localization is very Rare the upper extremity, trunk, and head and neck are most frequently affected. Intravascular fasciitis is also chiefly subcutaneous.
- 11. • Microscopy –Nodular fasciitis is composed of plump but regular spindle-shaped fibroblasts (or myofibroblasts) lacking nuclear hyperchromasia and pleomorphism. • Mitotic figures may be plentiful, but atypical mitoses would not be expected. • there is often growth in S- or Cshaped fascicles, and sometimes a storiform pattern. • multinucleated osteoclastlike giant cells
- 12. Nodular fascitis
- 13. Afeature of diagnostic significance is the presence of undulating wide bands of collagen lined on the sidesby spindlecells.
- 14. • SMA and MSA • but desmin positivity is rare • CD68 staining is present in the osteoclast-like giant • Keratin and S100 protein are typically negative.
- 15. Proliferative fasciitis and proliferative myositis • Definition • mass-forming subcutaneous proliferation characterized by large ganglion-like cells • plump fibroblastic / myofibroblastic • Proliferative myositis has the same cellular composition but occurs within skeletal muscle.
- 16. Proliferative fasciitis and proliferative myositis • Theskeletal muscles of the shoulder, thorax,and thigh are those most commonlyaffected. • Most patients are over the ageof45 years • Gross- ill defined scar-like indurations of the muscle .
- 17. • Microscopic- Both proliferative fasciitis and myositis contain plump fibroblastic/myofibroblastica • Thehallmark ganglion-like cell demonstrate large cells with rounded nuclei, prominent nucleoli, and abundant amphophilic to basophilic cytoplasm. ganglion-like cell
- 19. Myositis ossificans • It is areactive condition that is sometimesmistaken microscopically for osteosarcoma. • Theterm is inaccurate becausethe muscle may notbe involved, and inflammation is virtuallyabsent. • Ahistory of trauma is obtained in only half of the patients. • Themost common locations are the flexor musclesof the upper arm (especially the brachialis anticus), the quadriceps femoris, the adductor muscles of the thigh, the glutealmuscles,
- 20. • Microscopic- there is ahighly cellular stroma associated with new bone and, lesscommonly, cartilage formation. • Themost important diagnostic feature is provided by the maturation pattern(‘zonal phenomenon’), characterized by acentral cellular area, an intermediate zoneof osteoid formation, and aperipheral shell of highly organized bone
- 21. Low power view showing typical zonation with fasciitis-like features (centre right), immature osteoid (centre) and bone formation at the periphery (left).
- 22. Reactive endothelial proliferation resembling soft tissue sarcoma • Papillary endothelial hyperplasia • Spindle cell hemangioendothelioma
- 23. Papillary Endothelial Hyperplasia Masson’s tumor • Papillary endothelial hyperplasia is an exuberant, usually intravascular, endothelial proliferation that, in many respects,mimics an angiosarcoma. • almost always solitary • the skin, subcutaneous tissue, or even muscle with the head and neck region and the upper extremities. • The fingers especially are the most common sites
- 24. Primary lesions are usually tender nodules 2 cm in size, whereas secondary lesions occur because some preceding vascular abnormality increases in size.
- 25. • purple-red, multicystic mass containing clotted blood and • surrounded by a fibrous pseudocapsule
- 26. Microscopy • In the early lesion, the ingrowth of endothelium along the contours of the thrombus partitions it into coarse papillae with fibrin cores • In the well-established or typical lesion, myriad small delicate papillae project into the lumen • These papillae are composed of a single layer of endothelium surrounding a collagenized core. • The endothelial cells appear plump or swollen but lack significant pleomorphism and mitotic figures.
- 27. A: Early stage is characterized by thrombus with ingrowth of endothelial cells. B: Endothelium gradually subdivides the partially collagenized thrombus into coarse clumps C:followed by papillae
- 28. • A helpful point in the differential diagnosis is its intravascular location because angiosarcomas are almost never confined to a vascular lumen. • papillary endothelial hyperplasia lacks the frank tissue necrosis, marked pleomorphism, and high mitotic rate that characterize many angiosarcomas.
- 29. Spindle cell hemangioendothelioma • Any age, usually males, usually distal extremities • Low grade lesion which recurs commonly and may be multicentric, but only one reported metastases after repeated recurrence and radiation therapy • May be a hamartoma due to aberrations in local blood blow; perhaps should be called spindle cell hemangioma • Associated with Mafucci's syndrome
- 30. Microscopy • Cavernous hemangioma and Kaposi sarcoma like features • Cavernous spaces with solid areas composed predominantly of bland spindle cells • minor component of epithelioid ,often vacuolated, • endothelial cells, usually associated with irregular fascicles of smooth muscle fibers and adjacent malformed vessels
- 31. The image shows cavernous angiomatous areas and solid foci composed of bland spindle and epithelioid cells
- 32. • (a) cavernous blood vessels filled partly or completely with erythrocytes or thrombus admixed with cellular zones • (b) High-power view of juxtaposition of the cavernous and cellular areas illustrating blood-filled dilated vessels lined by flattened endothelial cells and spindle-shaped cellular components. There is no evidence of abnormal mitotic activity or nuclear atypia in spindled cells
- 33. Mass forming inflammatory histocytic and infective lesion resembling soft tissue sarcoma • Extranodal (Soft Tissue) Rosai-Dorfman Disease • Malakoplakia • Xanthogranulomatous pyelonephritis • Polyvinylpyrrolidone (PVP) reaction • Mycobacterial spindle cell nodule • Bacillary angiomatosis
- 34. Extranodal (Soft Tissue) Rosai-Dorfman Disease • Rosai-Dorfman disease is a polyclonal histiocytic disorder of uncertain etiology, which, although originally described as a lymph node disease • occurs in sundry locations, including soft tissue 10% of all cases • its appearance and immunophenotype most closely approximate an activated macrophage
- 35. • Microscopically, the lesions consist of sheets or syncytia of large, pale histiocytes with large, round, vesicular nuclei with some degree of • Mitotic figures are absent • The cytoplasm of the histiocytes may contain lymphocytes (emperipolesis), although this is seldom as striking as in the • Microabscesses, when present, suggest the possibility of an infectious process.
- 36. Extranodal Rosai-Dorfman disease characterized by sheets of pale histiocytes with voluminous cytoplasm.
- 37. • strongly express S-100 protein and, occasionally, • other histiocytic antigens, including CD1a. However, they do not contain Birbeck granules. • A feature of diagnostic significance • S-100 protein is useful for discriminating undifferentiated pleomorphic sarcomas • Rosai-Dorfman disease from Langerhans cell histiocytosis, cytologic differences between the proliferating
- 38. Malakoplakia • Malacoplakia is a rare inflammatory disease believed to represent an unusual host response to infection with a variety of organisms, including Escherichia coli, Klebsiella, and acid-fast bacilli. • The reaction results in the formation of yellow plaquelike lesions on the mucosal surface of the affected organs. • typically genitourinary tract, particularly the bladder, although it may affect the soft tissues of the retroperitoneum as well.
- 39. • Microscopy • It is characterized by sheets of pale, slightly granular, or vacuolated histiocytes (von Hansemann cells) containing PAS-positive, diastase-resistant inclusions in the cytoplasm • Lymphocytes, plasma cells, and neutrophils are typically abundant. • The distinctive Michaelis-Gutmann bodies, small calcospherites • numerous phagolysosomes, occasional bacterial forms, and lamellated crystalline
- 40. High-power view of malacoplakia showing Michaelis-Gutmann bodies (arrows) in occasional cells.
- 41. Xanthogranulomatous pyelonephritis • Definition / general • Rare, severe, atypical form of chronic pyelonephritis due to infection (E. coli, Proteus) or stones, but resembling renal cell carcinoma; correct preoperative diagnosis is unusual • Characterized by foamy histiocytes replacing renal parenchyma, due to
- 42. • Gross description • Multiple yellow nodules around calyces, may form a mass and be infiltrative • Numerous dilated calyces with yellow-brown calculi are seen. The central necrotic areas are surrounded by dense fibrosis
- 43. • Replacement of renal parenchyma with CD68+ foamy histiocytes, occasional multinucleated giant cells and inflammatory cells
- 44. • A feature of diagnostic significance • intraoperative urine culture may be helpful • Malakoplakia: Michaelis-Gutmann bodies • Renal cell carcinoma: Cells with clear cytoplasm may resemble histiocytes, but are keratin+, CD68-; arranged in compact, tubulocystic, alveolar or rarely papillary patterns; often glassy hyaline globules;) • Renal replacement lipomatosis: atrophic renal parenchyma is replaced by fatty tissue, not xanthoma cells
- 45. Polyvinylpyrrolidone (PVP) reaction • Polyvinylpyrrolidone (PVP) is a polymer of vinylpyrrolidone, which was used notably as a plasma expander during • Because of its hydroscopic properties, it has also been used as a retardant in various injectable medicines (hormones, antihypertensives, local anesthetics), as a clarifier in fruit juices, and as a resin in hair sprays.
- 46. Microscopy • these lesions are composed of numerous histiocytes massively engorged with PVP • The material appears glassy blue or blue-gray in sections stained with hematoxylin-eosin. • Typically, there are few inflammatory cells and no necrosis. • Giant cells are occasionally present and may be helpful in suggesting the diagnosis of a foreign body reaction.
- 47. PVP characteristically does not stain with Alcian blue and, therefore stains differently from all myxoid tumors of soft tissue, such as liposarcoma, chondrosarcoma, and chordoma. A feature of diagnostic significance • The best stains for demonstrating the cytoplasmic material are Congo red or Sirius red.
- 48. Mycobacterial pseudotumors • Mycobacterial pseudotumors, first recognized by Wood • most recently in AIDS patients in a variety of sites, most commonly lymph nodes but also skin/subcutis
- 49. • The lesions are analogous to those of histoid leprosy in that they consist of a tumorous proliferation of spindled and epithelioid histiocytes • arranged in vague fascicles and associated with occasional • chronic inflammatory cells • The cells are laden with numerous acid-fast bacilli easily demonstrable with appropriate stains ( • CD68 positive, confirming their histiocytic lineage
- 50. Bacillary angiomatosis • Usually not distinctly lobular • multiple pink, elevated skin lesions that may resemble a pyogenic granuloma. • Clusters of neutrophils within lesion • Amphophilic collections of organisms
- 51. • In the classic case, bacillary angiomatosis • consists of lobules of capillary-sized vessels lined by plump (epithelioid) endothelium with clear cytoplasm • Mild atypia and occasional mitotic figures may be present in the endothelial cells.
- 52. Benign connective tissue tumors resembling soft tissue sarcoma • Atypical and cellular benign fibrous histocytoma • Ancient schwannoma • Pleomorphic /spindle cell lipoma
- 53. Benign Dermatofibroma (Fibrous Histiocytoma/Sclerosing Hemangioma) • common skin • occurring on the extremities or trunk of young adults. • Gross: They present as small, firm, solitary nodules that are red to brown in color, often due to increased intraepidermal melanin or tumoral hemosiderin. • The cut surface is white to yellow or brown, depending on the proportions of fibrous tissue,lipid, and hemosiderin present
- 54. Gross appearance of a pedunculated cutaneous fibrous histiocytoma. The light color of the lesion is a result of the presence of large amounts of lipid. B: This dermatofibroma shows prominent hyalinization and pigmentation. C: Hemosiderin and multinucleated giant cells dominate in this zone of another dermatofibroma.
- 55. Histopathology. • The epidermis hyperplastic, with hyperpigmentation of the basal layer and elongation of the rete ridges, separated by a clear (Grenz zone) • exhibit a storiform pattern of interwoven, fascicled spindle cell • This is composed of fibroblast-like spindle cells, histiocytes, and blood vessels in varying proportions • Foamy histiocytes and multinucleate giant • cells containing lipid or hemosiderin • sometimes in large numbers, forming xanthomatous aggregates. • Capillaries may be plentiful in the stroma • “rounding up” of collagen fibers.
- 56. • nodular fasciitis, neurofibroma, and sclerotic leiomyoma.
- 57. Cellular Fibrous Histiocytoma • This is a rare, densely cellular variant with a fascicular to storiform growth • may mimic dermatofibrosarcoma protuberans (DFSP) • assists in making this differentiation factor XIIIa staining is often negative
- 58. B: Densely packed spindle cells are present, arranged in a storiform C: This DFSP exhibits an area with a prominent fibrosarcoma-like pattern. A: The tumor consists of spindle cells arranged in densely cellular fascicles with storiform areas.
- 59. Atypical Fibrous Histiocytoma • The atypical cells show enlarged, pleomorphic nuclei, sometimes referred to as monster cells • Mitoses of normal morphology may be evident. • Multinucleated giant cells with bizarre, large, hyperchromatic • nuclei with little cytoplasm or irregular, vesicular nuclei with abundant foamy cytoplasm may also occur • Focal necrosis may be seen. • Variable staining for • smooth muscle actin and CD34, with no staining • for factor XIIIa.
- 60. A: This tumor shows histiocyte-like cells with enlarged and pleomorphic nuclei with prominent nucleoli. B: At the border of this tumor the cells are arranged around individual collagen bundles in the pattern typical of the more usual form of dermatofibroma
- 62. Schwannoma(Ancient schwannoma) • Truly encapsulated neoplasms • Almost always solitary • Its most common locations are the flexor surfaces of the extremities, neck, mediastinum, retroperitoneum, posterior spinal roots, and cerebellopontine angle. • The great majority of casesoccur sporadically. • Asmall percentage of casesare associated with neurofibromatosis type
- 63. Schwannoma
- 64. • Ancient schwannomas are those displaying marked nuclear atypia of a degenerative type. • They are usually large tumors of long duration, are located in deep structures such as the retroperitoneum. • Degenerative changes include cyst formation, calcification, hemorrhage, and hyalinization • large numbers of siderophages and histiocytes. • One of the most treacherous aspects of this tumor is the degree of nuclear atypia encountered. • The Schwann cell nuclei are large,hyperchromatic, and often multilobed but lack mitotic figures
- 65. Gross specimen of a schwannoma of the retroperitoneum with extensive degenerative changes (ancient schwannoma). Tumors are characterized by areas of old and new hemorrhage, cyst formation, and calcification. Ancient schwannoma with cyst formation and interstitial hyalinization.
- 66. Ancient schwannoma with degenerative atypia and perivascular hyalinization. Note the lipofuscin-like pigment in the Schwann cells. Degenerative atypia in an ancient schwannoma.
- 67. • immunoreactivity for • S-100protein, • calretinin (incontrast to neurofibromas), • calcineurin, • basallaminacomponents vimentin, nerve growth factor receptor, lipocortin-1,and sometimes glial fibrillary acidic protein andKP-l
- 68. Spindle cell lipoma / Pleomorphic lipoma • Spindle cell and pleomorphic are circumscribed composed of a variable admixture of bland spindled cells, hyperchromatic rounded cells, and multinucleate giant cells associated with ropey collagen. • Sites of involvement • predominantly in the posterior neck and shoulder area. • Face, forehead, scalp,buccal-perioral area and upper arm are less common sites
- 69. Macroscopy • oval or discoid yellowish to greyish- white mass depending on the relative extent of the fatty and spindle cell components. • firmer texture than ordinary lipoma, • gelatinous texture.
- 70. Histopathology • spindle cell lipoma is composed of bland mitotically inactive spindled cells • thick rope-like collagen bundles are seen between the fat . • Large numbers of mast cells are often seen • show myxoid stromal changae or display slit-like cleavage spaces resembling vascular slits
- 71. • At the opposite end of the spectrum, pleomorphic lipoma is characterized by small spindled and rounded hyperchromatic cells • multinucleated giant cells with radially arranged nuclei in a"floretlike“ pattern, like petals of flowers.
- 72. • Immunophenotype • for CD34 and • may rarely be positive for S100 protein
- 73. THANK YOU • Ref • Recent advance vol 19 • LEVER’ S Histopathology of the Skin • WHO classification or bone and soft tissue tumors • sternbergs-diagnostic-surgical-pathology