We present a case of a 77-year-old female with a history of osteoarthritis who presented with a 6 month history of progressive weakness, intractable right hip/buttock pain and anemia of chronic disease. Serum protein electrophoresis (SPEP) did not show monoclonal protein but serum free Kappa and urine Beta-2 microglobulin were slightly elevated. Because of multiple MRIs showing findings of various lytic lesions, a bone marrow biopsy was performed to rule out multiple myeloma but results showed no monotypic plasma cell or evidence of carcinoma. Subsequent CT-guided bone biopsies from iliac crest and left tibia showed poorly differentiated metastatic carcinoma with extensive necrosis of unknown primary. Patient continued to have worsening pain, persistent vomiting and 13kg weight loss requiring hospitalization. A PET CT scan was performed for further evaluation and showed hypermetabolic nodularities in the lungs so she underwent a VATS with pleural implant excisional biopsy. Immunohistochemistry of this biopsy was consistent with ‘Epithelioid Angiosarcoma’. In concordance with her clinical presentation, it was deduced that the primary was bony in origin. She was started on Doxil every 4 weeks with Denosumab.
Angiosarcomas are rare malignancies of endothelial origin and can be broken down into cutaneous, visceral or soft tissue subtypes. Epithelioid angisarcoma is a rare type of angiosarcoma that is characterized by large cell with epithelioid features. It often metastasizes early in the disease process to lymph nodes, lung, soft tissues, skin and bone. It mimics poorly differentiated carcinoma through its epithelial appearance, and multiple myeloma via clinical symptoms and osseous finding on imaging. In this patient, the rapid deterioration testifies to the aggressive nature of the tumor, with 50% of the patients dying within 2 to 3 years of disease. Immunohistochemistry studies of the iliac and pleural biopsy of this patient revealed positive endothelial markers and cytokeratin and with clean bone marrow biopsy, multiple myeloma was ruled out. While histological analysis of a bone biopsy specimens were consistent with poorly differentiated carcinoma, biopsies were positive for Vimentin and negative for S100, which are strong indicators of angiosarcoma of epithelioid variant rather than carcinoma. The rarity of this tumor, similar microscopic appearance with other epithelioid neoplasm and similar clinical presentation with other tumors make diagnosing epithelioid angiosarcoma a challenging one. This is congruent with the literature, with a previous series reporting misdiagnosis in 3 of 10 cases.
Epithelioid angiosarcoma is associated with an aggressive clinical course that could easily be mistaken for other tumors given its low prevalence. A low threshold of clinical suspicion, in this case, persistent bone pain, should prompt a biopsy with correct immunochemistry studies to accurately diagnose this rare anomaly.
To cite this abstract:Lim HW, Joasil P. Pitfalls in the Diagnosis of Epithelioid Angiosarcoma. Abstract published at Hospital Medicine 2016, March 6-9, San Diego, Calif. Abstract 643. Journal of Hospital Medicine. 2016; 11 (suppl 1). https://www.shmabstracts.com/abstract/pitfalls-in-the-diagnosis-of-epithelioid-angiosarcoma/. Accessed October 14, 2019.