Qap (Anatomical Pathology) 

QAP Peer Review

AP193
Case History: F/14 rapidly enlarging lacrimal mass.
Intended diagnosis: Embryonal rhabdomyosarcoma. Contributed by:USK
Code Diagnosis Comment Score
anonymous Embryonal rhabdomyosarcoma (100%) Immunostains for myogenin, MyoD1, desmin, actin for confirmation.  100
anonymous Malignant small round cell tumor (100%). Morphologic appearances most compatible with embryonal rhabdomyosarcoma. Confirmation with immunostains (+ve myogenic markers - desmin, myogenin). The panel should include other stains including CD99, a cytokeratin and S-100 protein.  100
anonymous Malignant small round cell tumor, 100%, favor embryonal rhabdomyosarcoma. To confirm by positive immunostaining for desmin, actin and myogenin. Differential diagnoses: Ewing's sarcoma/ PNET (PAS positive, myoid markers negative); lymphoma (LCA positive)  100
anonymous EMBRYONAL RHABDOMYOSARCOMA. 100% Skeletal muscle differentiation to be confirmed by actin, desmin, Myo-D1 etc.  100
anonymous Embryonal rhabdomyosarcoma. (100%) Do myogenin stain to confirm.  100
anonymous Lacrimal gland - small round cell tumour DDX:1) embryonal rhabdomyosarcoma 90% 2)Ewing sarcoma/PNET Need ancillary tests (immunohistochemistry and/or EM) to reach definitive diagnosis  100
anonymous High grade malignant small round cell tumour, with differential diagnosis of 1. Rhabdomyosarcoma (90%) 2. Ewing sarcoma (10%) A panel of immunostains should be performed. Desmin, myogenin and MyoD1 will be positive in rhabdomyosarcoma, CD99 will be positive in Ewing sarcoma.  100
anonymous Malignant small round cell tumour 100% DDX includes rhabdomyosarcoma, malignant lymphoma. Suggest immunohistochemical staining for desmin, myogenin, TdT, CD99  100
anonymous Small blue round cell tumor of childhood. By the age and location, Embryonal rhabdomyosarcoma. Confirmed by IHC - SMA, Desmin, Calponin, Myogen, MyoD1, NSE, Synaptophysin, Chromogranin, CD99 to exclude other differential diagnosis.  100
anonymous LACRIMAL GLAND mass - MALIGNANT NEOPLASM, mesenchymal. (100%) Differential diagnosis includes mesenchymal chondrosarcoma, rhabdomyosarcoma, PNET/Ewing's sarcoma, hemangiopericytoma and synovial sarcoma. Immunohistochemical stains need to be performed.  90
anonymous Malignant small round blue cell tumour 100% DDx soft tissue leukaemic deposit, embryonal rhabdomyosarcoma, PNET, lymphoma Perform immunostains: -CD99 -desmin, actin, MyoD1 (rhabdomyosarcoma) -CD45, MPO (leukaemia, lymphoma) -cytokeratin (rhabdoid tumour) -synaptophysin (PNET)  100
anonymous Small round cell malignancy, favor embryonal rhabdomyosarcoma To perform immunostaining, including actin, desmin, myogenin etc for definitive diagnosis  100
anonymous Embryonal sarcoma Exclude striated muscle differentiation (embryonal rhabdomyosarcoma) with desmin and muscle specific actin stains.  90
anonymous Primitive small round cell tumour of children, favour embryonal rhabdomyosarcoma. Probability: 100% nil  100
anonymous Primitive small round cell tumour of children, favour embryonal rhabdomyosarcoma nil  100
anonymous Embryonal rhabdomyosarcoma 100% Confirm by immunostains for actin, desmin and MyoD1  100
anonymous Small round cell tumor, differential diagnosis include embryonal rhabdomyosarcoma (80%) and other SRCTs (20%, eg. Ewing/PNET, myeloid sarcoma, neuroblastoma, melanoma, myoepithelioma, synovial sarcoma etc) Immunohistochemical stains for myogenin, cytokeratin, desmin, neural markers, S100 proteins, CD99, MPO, LCA, HMB45, calponin would help diagnosis. Cytogenetics for characteristic translocations are also helpful.  100