Chapter 26: Soft Tissue Tumors Flashcards
What tendencies tend to differ between benign and malignant tumors?
Superficial - more benign than deep
Large tumors more malignant
Rapidly growing more malignant
Calcification exists in both
Benign avascular, malignant hypervascular
A young patient presents with a rapidly growing lesion following trauma of the forearm.
The lesion is hypercellular with abundant mitoses and numerous polymorphic spindle-shaped fibroblasts and myofibroblasts in a myxoid stroma.
Nodular fascitis
A patient presents with a large, fiirm, whitish lesion with poorly demarcated borders and a whorled cut appearance.
Microscopic examination reveals sheets and interdigitating fascicles of beingn-appearing spindle cells with little mitotic activities.
Fibromatosis
Mutations in APC gene found in familial adenomatous polyposis. Binds beta-catenin, enhances degradation. If left alone, promotes Wnt pathway signaling, development of disease.
Palmar fibromatosis (Dupuytren contracture): Most common, can be bilateral, flexion-contracture of fingers.
Plantar fibromatosis: Involves plantar aponeurosis
Penile fibromatosis: Peyronie disease mass in penile shaft, curves toward one side (penile strabismus)
A middle-aged patient presents with a mass around the knee. It has arisen from a deep connective tissue (fascia, scar tissue, periosteum, and tendons.
The mass is sharply demarcated and exhibits necrosis and hemorrhage.
Histological examination shows malignant-appearing spindle cells that form interlacing bundles and fasicles, produces a “herringbone” pattern.
Fibrosarcoma.
Congenital version contains ETV6-NTRK3 fusion gene, poor prognosis.
A patient presents with a unencapsulated gray-white tumor with areas of hemorrhage and necrosis.
Microscopic examination shows an anaplastic tumor with spindle cells, plump polygonal cells, bizarre tumor giant cells, an abnormal mitosis, and scattered chronic inflammatory cells.
Undifferentiated pleomorphic sarcoma (Malignant fibrous histiocytoma)
Prognosis determined by grade-like characteristics.
A patient presents with a tumor of mature adiopcytes with small eccentric nuclei.
Encapsulated, soft, yellow lesion.
Lipoma.
An angiolipoma is similar but has extensive vascular proliferation. Often multiple and painful.
A patient presents with a mass with necrosis, hemorrhage, and cysts. On histology, a malignant-appearing cell with univacuolated or multivacuolated cytoplasmic fat vesicles indenting the nucleus.
Liposarcoma
Characteristic cell is the lipoblast.
Myxoid/round cells: Have signet ring lipoblasts, primitive round cells in myxoid stroma. Have TLS/FUS gene product.
Atpical lipomas/well diff: MDM2 gene, inhibit p53
A child presents with a tumor with striated muscle diffedrentiation.
Histology shows some cells with cross-striations.
Rhabdomyosarcoma
Below is an alveolar rhabdomyosarcoma - arranged in clusters that look like an alveolar pattern. Intense eosinophilia. PAX3-FKHR or PAX7-FKHR gene fusions.
List the smooth mucle tumors
Leiomyoma and leiomyosarcoma
EBV-associated smooth muscle tumors: Immunocompromised patients (HIV) or post-transplant.
A patient presents with a mass near a joint. On gross exam, circumscribed round mass attached to a tendon. Tumor surrounded by glistening pseudocapsule. Hemorrhage, necrosis, and calcification are seen.
Microscopically shows a biphasic pattern. Fluid-filled glandular spaces lined by epithelium-like tumor cells embedded in sarcomatous, spindle cell background.
Synovial sarcoma
SYT-SSX1 or SYT-SSX2. Chromosome 18 with chromosome X.
