MISCELLANEOUS/GENERAL

Question 1

SRBCT adults

Answer 1

• Lymphoma
• Small cell NE carcinoma: Older adults, any organ. CK+, NE markers +, CK20 -, TTF1+ in lung & some non-lung.
• Merkel cell carcinoma: 60-70yo, dermis of head and extremities. CK +, NE markers +, CK20 +(dot like).
• Desmoplastic SRCT: mean 21yo, serosal cavities. WT1+, CK+. Molecular: t(11,22) EWS-WT1.
• Small cell Osteosarcoma: Peaks 20s and 50s. Around knee. Need osteoid production for dx.
• Mesenchymal chondrosarcoma: 10 to 40yo. Axial skeleton. Need chondroid diferentiation for dx. SOX 9+ t(9,22).
• Round cell liposarcoma/ cellular myxoid LS: Peak 30s. Soft tissue of thigh or retroperitoneum. Chicken wire vessels, lipoblasts. t(12,16) TLS-CHOP, t 12,22) EWS- CHOP.
• Synovial sarcoma: Any age. Extremities, para-articular, H & N. CK, EMA, CD99, calponin +. t (X,18) SYT-SSX.
• Olfactory neuroblastoma: Peaks 15 & 55yo. Roof of nasal fossa. Fibrillar rosettes, neuropil. NE markers +, sustentacular S100, CK focal.
• Also: Ewing sarcoma/PNET, small cell melanoma