Qap (Anatomical Pathology) 

QAP Peer Review

AP212
Case History: M/43, Transverse colon tumor
Intended diagnosis: Desmoplastic small round cell tumor, colon. Contributed by:KFT
Code Diagnosis Comment Score
anonymous Malignant small round cell tumour, favour desmoplastic small round cell tumour (100%) Tumour cells may be positive for CK, Desmin, EMA, vimentin and NSE.  100
anonymous Malignant neurogenic tumor: Melanotic neuroectodermal tumor (50%). Neuroblastoma (50%) nil  50
anonymous Gastrointestinal stromal tumor (with possible post-Gleevac effect). 80% DDx: Schwannoma. 20% More clinical history should be given in the first place! Is there a history of previous GIST? Treatment? The Dx of GIST is confirmed with +ve immunostains (CD117 & CD34) while S-100 protein positivity would be more in favour of a schwannoma.  20
anonymous Desmoplastic small round cell tumor, 100%. Confirm by immunohistochemical studies (cytokeratin, desmin and neurone specific enolase all positive.  100
anonymous Small blue round cell tumor, consistent with intra-abdominal desmoplastic small round cell tumor 70%, ddx: small cell carcinoma 30%. Confirm by CK+, NSE+, desmin+, SMA-, EWS-WT1 protein+. For small cell ca, CK+(punctate perinuclear), chromogranin+, synaptophysin+. Immunostains for other remote ddx eg. lymphoma, undifferentiated ca and melanoma(pigments+).  100
anonymous Desmoplastic small round cell tumor.(100%) Can do cytokeratin, vimentin, desmin and WT1 stains to help diagnosis. Or do RT-PCR for EWS-WT1 fusion gene transcript to confirm diagnosis.  100
anonymous TREATED GASTROINTESTINAL STROMAL TUMOUR -100% nil  10
anonymous Malignant small blue cell tumour ddx: Neuroblastoma (70%), Ewing's sarcoma/PNET (20%), malignant melanoma (<10%), rhabdomyosarcoma (<10%), small cell carcinoma (<10%) Perform immunohistochemical stain NSE, synaptophysin, chromogranin, neurofilament, CD 99, S-100 protein, HMB 45, BCK, desmin, myoglobin, myogenin  60
anonymous Intra-abdominal desmoplastic small round cell tumour 100% nil  100
anonymous Schwannoma with presence of melanin and cellular area nil  10
anonymous Infiltration by malignant small round cell NEOPLASM The histologic differential diagnoses include desmoplastic small round cell tumour, gastrointestinal stromal tumour and lymphoma. Immunohistochemcial stains like dismin, cytokeratin, NSE, CD34, c-kit and lymphoid markers are suggested for reaching a definitive diagnosis. The hyaline degeneration of subserosa and subserosal vessels is not typical and secondary changes like treatment effect induced by radiotherapy or chemotherapy needs to be considered.  60
anonymous Small cell tumor The differential disgnoses include primitive neuroectodermal tumor, desmoplastic small round cell tumor, small cell melanoma and small cell carcinoma. Suggest performing immunohistochemical study to differentiate - PNET would be postive for CD99, DSRCT for CD99, cytokeratin and smooth muscle markers, melanoma for S100 and HMB45, and small cell carcinoma for CAM5.2.  60
anonymous Dx: small cell tumor. DDx: desmoplastic small round cell tumour and small cell carcinoma. Will perform epithelial, neuroendocrine and muscle marker. 100% Probability nil  80
anonymous Intra abdominal desmoplastic small round cell tumor. 100%. t(11, 22) (p13: q12) cytogenetic finding for confirmation  100
anonymous Small round cell tumor, favour desmoplastic small round cell tumor (100%) Immunohistochemical staining for AE1/AE3, EMA, NSE, desmin, SMA, LCA.  100