Histosminaire By JeanFranois Dermine R 4 March 31

Histoséminaire By Jean-François Dermine R 4 March 31 2010

Clinical informations 49 year-old Libanese man. n Back pain since 1984. n 2009 presents at Hôpital Sacré-Coeur with pain in both legs. n Imaging: osteolytic lesions, bilaterally in iliac wings, femurs, tibias, fibulas, humeri and left radius. n Open biopsy performed in June 2009 n

Differential diagnosis Metastatic carcinoma n Multiple myeloma n Lymphoma n Metastatic melanoma n Mesenchymal neoplasm n

Mitoses 20 per 10 HPF

Immunostains Vimentin+ n AE 1/AE 3 focally + n S 100 n Muscle markers n CD 31, CD 34+ n

Clinical informations n Biopsy results n High grade angiosarcoma

AE 1/AE 3

CD 31

CD 31

Fli-1

Malignant Epithelioid Neoplasm, morphologically and immunohistochemically consistent with Epithelioid Hemangioendothelioma.

Epithelioid hemangioendothelioma First described by Weiss and Enziger in 1982 n WHO: An angiocentric vascular tumor with metastatic potential, composed of epithelioid cells arranged in short cords and nests set a distinctive myxohyaline stroma. n

Epithelioid hemangioendothelioma n Epidemiology: Rare n Affects all ages except early childhood n Affects both sexes equally n n Presentation: Solitary soft tissue mass n Rarely multifocal in a localized region (liver, bone) n

Epithelioid hemangioendothelioma of bone EHE of bone is described under angiosarcoma in the WHO. n Frequent in lower extremities, axial skeleton, and paired bones n Presents with pain n

Epithelioid hemangioendothelioma n Histhopathology: Arises in a vessel an expends it n Short strands, cords or solid nests of slightly spindled eosinophilic endothelial cells (epithelioid) n Intracytoplasmic lumina (sometimes with red blood cells inside) n Rarely produces vascular channels n

Epithelioid hemangioendothelioma n Typical IHC: CD 31+ n CD 34+ n Fli-1+ n Focal cytokeratins positivity in 20 -30% of cases n n Molecular: n t(1; 3) in 2 lesions

Epithelioid hemangioendothelioma n Prognostic factors: Recurrence rate of 10 -15% n Metastatic rate of 20 -30% n Mortality 10 -20% n

Epithelioid hemangioendothelioma n Atypical features: Marked nuclear atypia n High mitotic activity (>1/10 HPF) n Spindling of the cells n Necrosis n

Weibel-Palade bodies

Angiosarcoma of bone 1% of malignant bone tumors. n A third are multifocal. n Occurs in femur, humerus, pelvic bone, vertebrae and ribs. n Can have epithelioid morphology. n Epithelioid angiosarcoma can also have intracytoplasmic lumina. n

Clinical follow-up Patient treated palliatively with Cisplatinum. n August 2009: a 3, 8 cm mass is found in the left cardiac atrium. n Died November 2009. (No autopsy was performed) n

Conclusion Epithelioid hemangioendothelioma is vascular tumor with clinical behavior intermediate between benign hemangioma and angiosarcoma. n EHE mimicks other tumors. n EHE can be suspected when intracyplasmic lumina are present. n With frank malignant features, a diagnosis of angiosarcoma is acceptable. n

Concluding remarks n Beware of epithelioid lesions of bone. Rule out carcinoma and melanoma. n If vascular, make distinction between EHE and angiosarcoma. n

Contributors Dr Louis Bégin n Dr Ayoub Nahal n