Surgical Pathology M.01 Soft Tissues 2026 PDF

PCCSOM PCCSOM 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES...

PCCSOM PCCSOM 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES A.4. COVENTIONAL LIPOMA SURGICAL PATHOLOGY LECTURE SIMPLE KARYOTYPE COMPLEX KARYOTYPE Most common subtype LECTURER: DR. ARLENE QUITASOL, MD Like many leukemias and Aneuploid or polyploid Well encapsulated mass of mature adipocytes DATE: September 24, 2024 lymphomas, sarcomas are Demonstrate multiple, Usually arises in the subcutis of the proximal often euploid tumors with severe chromosomal extremities and trunk, most frequently during TOPIC OUTLINE a single, or limited gains and losses, none middle adulthood. I. SOFT TISSUES number, of chromosomal of which are recurrent Infrequently, lipomas are large, intramuscular, and II. TUMORS OF ADIPOSE TISSUE changes that occur early More common in adults poorly circumscribed III. FIBROUS TUMORS in tumorigenesis and are and tend to be Soft, mobile, and painless (except angiolipoma) IV. SKELETAL TUMORS specific enough to serve morphologically A.1. ANGIOLIPOMA Usually cured by simple excision V. SMOOTH MUSCLE TUMORS as diagnostic markers. pleomorphic VI. TUMORS OF UNCERTAIN ORIGINS Most commonly arise in Examples include B. LIPOSARCOMA younger patients and tend leiomyosarcomas and to have a monomorphic undifferentiated One of the most common sarcomas of adulthood I. SOFT TISSUE appearance sarcomas Occurs in people in their 50s to 60s in the deep soft Non-epithelial tissue excluding the skeleton, joints, microscopically tissues of the proximal extremities and in the central nervous system, hematopoietic and lymphoid Examples include the retroperitoneum. tissues. Ewing sarcoma, and Amplification of 12q13-q15 (well-differentiated With the exception of skeletal muscle neoplasms, synovial sarcoma liposarcoma) benign soft tissue tumors outnumber their malignant Amplification of t (12;16) (myxoid liposarcomas) counterparts, the sarcomas, by 100-fold. Pathologic classification integrates morphology (e.g., MDM2 In the United States, the incidence of soft tissue muscle differentiation), immunohistochemistry and o One of the key genes in the amplified region sarcomas is approximately 12,000 per year, which is less than 1% of all cancers W molecular diagnostics In addition to accurate diagnosis, grade (degree of g of chromosome 12q encodes a potent inhibitor of p53. Sarcomas cause 2% of all cancer mortality, reflecting differentiation) and stage (size and depth) are A.2. SPINDLE CELL LIPOMA Pleomorphic liposarcomas contain complex their aggressive behavior. important prognostic indicators. karyotypes without reproducible genetic Most soft tissue tumors arise in the extremities, abnormalities especially the thigh. Approximately 15% arise in children but the incidence MORPHOLOGY increases with age. Three morphologic subtypes: WELL DIFFERENTIATED LIPOSARCOMA PATHOGENESIS - Contains adipocytes with scattered atypical C Majority of sarcomas are sporadic and have no known spindle cells predisposing cause. MYXOID LIPOSARCOMA Small minority of soft tissue neoplasms are associated - Contains abundant basophilic extracellular with germline mutations in tumor suppressor genes matrix, arborizing capillaries and primitive cells (neurofibromatosis 1, Gardner syndrome, Li-fraumeni at various stages of adipocyte differentiation syndrome, Osler-Weber Rendu syndrome) reminiscent of fetal fat Few tumors can be linked to known environmental II. TUMORS OF ADIPOSE TISSUE PLEOMORPHIC LIPOSARCOMA exposures such as radiation, burns or toxins. A.3. MYELOLIPOMA - Consists of sheets of anaplastic cells, bizarre Origin of sarcomas is unknown nuclei and variable amounts of immature Tumors arise from pluripotent mesenchymal stem cells, A. LIPOMA adipocytes (lipoblasts) which acquire somatic “driver” mutations in oncogenes Benign tumor of fat and tumor suppressor genes. Most common soft tissue tumor of adulthood Subclassified according to morphologic and/or KARYOTYPIC COMPLEXITY characteristic molecular features: Classification of soft tissue tumors continues to evolve o ANGIOLIPOMA as new molecular genetic abnormalities are identified. o SPINDLE CELL LIPOMA Clinically, soft tissue tumors range from benign, self o MYELOLIPOMA limited lesions that require minimal treatment to o CONVENTIONAL LIPOMA intermediate grade, locally aggressive tumors with o FIBROLIPOMA minimal metastatic risk to highly aggressive malignancies with significant metastatic risk and mortality. NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 1 | 7 NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 2 | 7  PCCSOM PCCSOM 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES All types of liposarcoma recur locally and often Contain mutations in the APC or β-catenin genes, both Embryonal: the most common soft tissue sarcoma of repeatedly unless adequately excised of which lead to increased Wnt signaling childhood and adolescence, usually before age 20 Well-differentiated variant –indolent Majority of tumors are sporadic, but individuals with o Botryoid variant of embryonal Myxoid/round cell type -intermediate in its malignant familial adenomatous polyposis (Gardner syndrome) rhabdomyosarcoma has the best prognosis behavior who have germline APC mutations are predisposed to o Pediatric forms often arise in the sinuses, head Pleomorphic variant usually is aggressive and frequently deep fibromatosis and neck and genitourinary tract, locations that metastasizes do not normally contain much skeletal muscle MORPHOLOGY Pleomorphic: seen predominantly in adults Gray, white, firm, poorly demarcated masses varying o Pleomorphic subtype is often fatal III. FIBROUS TUMORS from 1 to 15cm in greatest diameter. Alveolar rhabdomyosarcoma frequently contains Rubbery and tough, and have marked infiltration of fusions of the FOXO1 gene to either the PAX3 or the A. NODULAR FASCIITIS surrounding muscle, nerve and fat. PAX7 gene, rearrangements marked by the presence Cytologically bland fibroblasts arranged in broad of (2;13) or (1;13) translocations, respectively. sweeping fascicles amid dense collagen are the PAX3 Self-limited fibroblastic and myofibroblastic proliferation - Transcription factor that initiates skeletal muscle Typically occurs in young adults in the upper extremity characteristic histologic pattern B.1.1. PALMAR (DUPUYTREN CONTRACTURE) Histology resembles scar differentiation, and the chimeric PAX3-FOXO1 History of trauma is present in approx.C 25% of cases Irregular or nodular thickening of the palmar fascia fusion protein interferes with the gene Tumors grow rapidly over a period of several weeks or either unilaterally or bilaterally (50%) expression program that drives differentiation, a months, typically no larger than 5 cm Attachment to the overlying skin causes puckering and mechanism like many of the transcription factor Identification of t(17;22) that produces a MYH9-USP6 dimpling. fusion proteins that are found in various forms fusion gene indicates that it is a clonal, but self-limited, Slowly progressive flexion contracture develops that of acute leukemia. proliferation. mainly affects the fourth and fifth fingers of the hand Aggressive neoplasms that are usually treated with surgery Typically spontaneously regresses and if excised, it rarely and chemotherapy, with or without radiation therapy recurs. Histologic type and location of the tumor influence survival MORPHOLOGY Arises in the deep dermis, subcutis, or muscle. MORPHOLOGY Grossly the lesion is less than 5cm, circumscribed, or A.1. EMBRYONAL RHABDOMYOSARCOMA slightly infiltrative. Presents as soft gray infiltrative mass. Richly cellular and contains plump, immature-appearing Tumor cells mimic skeletal muscle at various stages of fibroblasts and myofibroblasts arranged randomly or in In addition to possibly being disfiguring or disabling, embryogenesis and consist of sheets of both primitive short fascicles reminiscent of tissue culture fibroblasts deep-seated fibromatosis is occasionally painful round and spindled cells in a myxoid stroma A gradient of maturation (zonation) from cellular, loose, Because of the extensively infiltrative nature, complete Rhabdomyoblasts with visible cross-striations maybe and myxoid to organized and fibrous is typical excision is often difficult present. Cells vary in size and shape(spindle to stellate)and have conspicuous nucleoli; mitotic figures are abundant Recent efforts have concentrated on medical therapy A.2. SARCOMA BOTRYOIDES B.1.2. PLANTAR with cyclooxygenase 2 inhibitors, tyrosine kinase Lymphocytes and extravasated red blood cells are Variant of embryonal rhabdomyosarcoma that Common in young patients, inhibitors, or hormonal blockade (tamoxifen) common but neutrophils are unusual develops in the walls of hollow, mucosal-lined unilateral and without contractures structures, such as the nasopharynx, common bile B. FIBROMATOSES IV. SKELETAL TUMORS duct, bladder, and vagina. B.1.3. PENILE (PEYRONIE DISEASE) Palpable induration or mass on the dorsolateral Skeletal muscle neoplasms, in contrast to other Where the tumors about the mucosa of an organ, they aspect of the penis mesenchymal histotypes, are almost all malignant form a submucosal zone of hyper cellularity called the B.1. SUPERFICIAL FIBROMATOSIS CAMBIUM LAYER. infiltrative fibroblastic proliferation that can cause local May cause abnormal curvature of the shaft, Benign variant, rhabdomyoma, is frequent in individuals deformity but has an innocuous clinical course. constriction of the urethra, or both with tuberous sclerosis A.3. ALVEOLAR RHABDOMYOSARCOMA All forms of superficial fibromatosis affect males more Traversed by a network of fibrous septae that divide frequently than females B.2. DEEP FIBROMATOSIS (DESMOID TUMOR) A. RHABDOMYOSARCOMA the cells into clusters or aggregates, creating a crude characterized by nodular or poorly defined broad Large, infiltrative masses that frequently recur but do Malignant mesenchymal tumor with skeletal muscle resemblance to pulmonary alveoli. not metastasize fascicles of fibroblasts in long, sweeping fascicles, differentiation. Those in the center of the aggregates are discohesive, surrounded by abundant dense collagen. Most frequent in the teens to 30s, predominantly in Three subtypes are recognized: while those at the periphery adhere to the septae. In about 20% to 25% of cases, the palmar and plantar women o ALVEOLAR(20%) Tumor cells are uniform round, with little cytoplasm— fibromatoses stabilize and do not progress, in some Abdominal fibromatosis generally arises in the Musculo- o EMBRYONAL (60%) cross striations are not a common feature instances resolving spontaneously. aponeurotic structures of the anterior abdominal wall o PLEOMORPHIC(20%) Some recur after excision, particularly the plantar but tumors can arise in the limb girdles or the variant. mesentery NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 3 | 7 NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 4 | 7  PCCSOM PCCSOM 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES VI. TUMORS OF UNCERTAIN ORIGIN B. UNDIFFERENTIATED PLEOMORPHIC SARCOMA B. LEIOMYOSARCOMA Large proportion of tumors do not recapitulate any Includes malignant mesenchymal tumors with high- Accounts for 10% to 20% of soft tissue sarcomas known mesenchymal lineage grade, pleomorphic cells that cannot be classified into Occur in adults and afflict women more frequently Includes examples with simple and complex karyotypes another category by a combination of histomorphology, than men immunophenotype, ultrastructure or molecular Most develop in the deep soft tissues of the A. SYNOVIAL SARCOMA genetics. extremities and retroperitoneum Despite advances in molecular characterization of Particularly deadly form arises from the great vessels, Can present in locations (chest wall, head and neck) that sarcomas, UPS represents the largest category of adult especially the inferior vena cava. lack synovium and their morphologic features are sarcomas. Complex genotypes that stem from underlying defects inconsistent with an origin from synoviocytes. Most arise in the deep soft tissues of the extremity, that lead to profound genomic instability Account for approximately 10% of all soft tissue sarcomas especially the thigh of middle aged or older adults. and rank as the fourth most common sarcoma. Diagnosis of malignant fibrous histiocytoma (MFH), V. SMOOTH MUSCLE TUMORS MORPHOLOGY Most occur in people in their 20s to 40s. sometimes used interchangeably with UPS, has fallen C Leiomyosarcomas present as painless firm masses. Retroperitoneal tumors maybe large and bulky and Patients usually present with a deep-seated mass that has been present for several years. out of usage because 1. the category included both undifferentiated A. LEIOMYOMA cause abdominal symptoms. Characteristic chromosomal translocation t(x;18)(p11;q11) tumors and others that were reclassified with producing SS18-SSX1SSX2, or -SSX4 fusion genes that immunohistochemistry or molecular methods benign tumor of smooth muscle Consist of eosinophilic spindle cells with blunt-ended, C often arises in the uterus hyperchromatic nuclei arranged in interweaving encode chimeric transcription factors. Treated aggressively with limb sparing surgery and 2. no consensus exists for the morphologic definition of fibro histiocytic Most common neoplasm in women fascicles. Develop in 77% of women and, depending on their Ultrastructurally, the tumor cells contain bundles of frequently chemotherapy Reproducible genetic changes are not typical of UPS - number, size, and location, may cause a variety of thin filaments with dense bodies and pinocytic 5-year survival varies from 25% to 62%, related to stage Most tumors are aneuploid with multiple structural and symptoms including infertility and patient age numerical chromosomal changes. 2 vesicles, and individual cells are surrounded by basal May also arise from the erector pili muscles (PILAR lamina. Common sites of metastases are the lung and occasionally Treated with surgery and adjuvant chemotherapy LEIOMYOMAS) found in the skin, nipples, scrotum, and Immuno histochemically, they stain with antibodies to the regional lymph nodes. and/or radiation labia and rarely in the deep soft tissues and the smooth muscle actin and desmin. IHC: (+) sm musc actin, desmin Prognosis is generally poor, with metastases arising in muscularis of the gut. MORPHOLOGY 30% to 50% of cases. L Pilar leiomyomas may be multiple and painful. Phenotype of multiple cutaneous leiomyomas may be A.1. MONOPHASIC SYNOVIAL SARCOMA MORPHOLOGY transmitted as an autosomal dominant trait that is also Consists of uniform spindle cells with scant cytoplasm Usually large, grey, white fleshy masses and can grow associated with uterine leiomyomas and renal cell and dense chromatin growing in short, tightly packed quite large (10to20cm) depending on the anatomic g carcinoma—hereditary leiomyomatosisand renal cell fascicles. compartment cancer syndrome Tumors may calcify Necrosis and hemorrhage are common o Associated with a germline loss-of-function mutation in Consist of sheets of large, anaplastic spindled to the fumarate hydratase gene located on chromosome A.2. BIPHASIC TYPE polygonal cells with hyperchromatic irregular, 1q42.3 contains, in addition to the spindle cell component sometimes bizarre nuclei Usually 1 to 2 cm above, gland-like structures composed of cuboidal to Mitotic figures, including atypical non-symmetric forms, Composed of fascicles of densely eosinophilic spindle columnar epithelioid cells are abundant as is coagulative necrosis. cells that tend to intersect each other at right angles Immunohistochemistry is helpful in identifying these Tumor cell slack differentiational on recognized along C Tumor cells have blunt-ended, elongated nuclei and tumors, since the tumor cells, especially in the biphasic lineages show minimal atypia and few mitotic figures type, are positive for epithelial markers (e.g.,keratins), Solitary lesions are easily cured differentiating them from most other sarcomas. ----------------------------------END------------------------------------------ Multiple tumors may be so numerous that complete surgical removal is impractical Treatment depends on tumor size, location, and grade. Superficial or cutaneous leiomyosarcomas are usually small and have a good prognosis, whereas those of the retroperitoneum are large, cannot be entirely excised, and cause death by both local extension and metastatic spread, especially to the lungs NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 5 | 7 NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 6 | 7  PCCSOM 2026 SURGICAL PATHOLOGY M.01 SOFT TISSUES CHECKPOINT! TRUE OR FALSE: Sporadic MORPHOLOGIC SUBTYPES OF LIPOSARCOMA 1. Majority of sarcomas are familial with known A. WELL DIFFERENTIATED LIPOSARCOMA predisposing cause. B. MYXOID LIPOSARCOMA 2. Conventional lipoma are painless except angiolipoma. C. PLEOMORPHIC LIPOSARCOMA 3. Leiomyoma is benign tumor of smooth muscle that often arises in the uterus is the most common neoplasm B 15. Contains abundant basophilic extracellular matrix, arborizing capillaries and primitive cells at various stages in women. of adipocyte differentiation reminiscent of fetal fat A 4. Skeletal muscle tumors are mostly malignant in contrast 16. Contains adipocytes with scattered atypical spindle cells to other mesenchymal histotypes. Extremities 17. Consists of sheets of anaplastic cells, bizarre nuclei and 5. Most soft tissue tumors arise in the truncal area. variable amounts of immature adipocytes (lipoblasts) RHABDOMYOSARCOMA SUBTYPES 18. True of Deep Fibromatosis, except: A. EMBRYONAL RHABDOMYOSARCOMA a. Aka Desmoid Tumor B. SARCOMA BOTRYOIDES b. Large, infiltrative masses that frequently recur C. ALVEOLAR RHABDOMYOSARCOMA and metastasize c. Abdominal fibromatosis generally arises in the C 6. Traversed by a network of fibrous septae that divide the Musculo-aponeurotic structures of the anterior cells into clusters or aggregates, creating a crude abdominal wall but tumors can arise in the limb resemblance to pulmonary alveoli. girdles or the mesentery B 7. Develops in the walls of hollow, mucosal-lined d. Contain mutations in the APC or β-catenin genes, structures, such as the nasopharynx, common bile duct, both of which lead to increased Wnt signaling bladder, and vagina. 8. Tumor cells mimic skeletal muscle at various stages of 19. Sarcoma botryoides forms a submucosal zone of hyper A embryogenesis and consist of sheets of both primitive cellularity called the ____________. Cambium layer round and spindled cells in a myxoid stroma 20. A benign smooth muscle tumor that arises in erector pili is A. MDM2 Pili leomyoma called ________. B. PAX3 C. MYH9-USP6 fusion gene A. Conventional B. Synovial A 9. One of the key genes in the amplified region of C. Leiomyoma chromosome 12q encodes a potent inhibitor of p53. D. Embryonal B 10. Transcription factor that initiates skeletal muscle E. Fibromatosis differentiation, and the chimeric fusion of protein F. Lipoma interferes with the gene expression program that drives differentiation F 21. Most common benign tumor of adulthood. C 11. Produced by t(17;22 and its production indicates that C 22. Most common neoplasm in women. Nodular Fasciitis is clonal, but self-limited proliferation. & 23. Most common rhabdomyosarcoma subtype. 24. Most common subtype of lipoma SUBTYPES OF FIBROMATOSES B 25. Fourth most common sarcoma. A. Palmar B. Plantar ANSWER: C. Penile 25. 24. 23. 22. 21. 20. 19. 18. 17. 16. 15. 14. 13. 12. 11. 10. 9. 8. 7. 6. 5. 4. 3. 2. 1. ↳ B A D C F Pilar Leiomyomas Cambium Layer B C A B A B C C B A A B C False: Extremities True True True False: Sporadic 12. May cause abnormal curvature of the shaft, constriction of the urethra, or both 13. Unilateral and without contractures 14. Slowly progressive flexion contracture develops NOTE TAKER: ABULENCIA, BALDOS, ADRADOS, MARIANO Page 1 | 7