Courtney Ann Coursey Moreno MD, Presenter: Nothing to Disclose

Salutario Jose Martinez MD, Abstract Co-Author: Nothing to Disclose

Emily N. Vinson MD, Abstract Co-Author: Nothing to Disclose

Brian Brigman, Abstract Co-Author: Nothing to Disclose

Leslie Dodd MD, Abstract Co-Author: Nothing to Disclose

To describe MR imaging, pathologic, and clinical characteristics of soft tissue angiomatoid fibrous histiocytoma (AFH).

The MR imaging studies of six cases of pathology-proven AFH were compiled from a single institution, the largest single institution series to date. Features evaluated included lesion location, morphology, margin, predominant T1 and T2 signal, and enhancement pattern. Specific features including presence of alternating layers of high and low signal around the periphery of the lesion ("double rim" sign), infiltrating cords of tumor cells ("Medusa head" sign), cystic-solid pattern, and fluid-fluid levels were assessed. Pathologic findings and clinical presentation and outcome were reviewed.

Mean patient age was 23 years (range 3-46 yrs; 3 male, 3 female). Lesions occurred in the upper extremity (n=3) and lower extremity (n=3). All tumors were primarily cystic. Five tumors were located in the subcutaneous tissues, and one was intramuscular. Primary tumors were surrounded by a low T1 and low T2 signal fibrous capsule with hemosiderin staining. A high signal lymphocytoplasmic infiltrate was visible in T2 and post contrast images as a high signal rim around the low signal capsule ("double rim" sign). Infiltrating cords of tumor cells extended through capsular defects ("Medusa head" sign). Fluid-fluid levels were variably present. Post-contrast imaging demonstrated the cystic component, enhancement of tumor cell nodularity, and the lymphocytoplasmic infiltrate. Recurrent tumors appeared as multiple 1-1.5 cm masses in the subcutis with peripheral enhancement, variable fluid-fluid levels, and were often misinterpreted as post-surgical change. Clinically, patients were often thought to have benign lesions such as hematomas at initial presentation and underwent marginal resection rather than the preferred treatment of wide excision. Five patients experienced local tumor recurrence, and one patient developed distant metastatic disease (mean follow-up 3.6 years).

A predominantly well-circumscribed, primarily cystic mass with a low signal capsule and infiltrating cords of tumor cells suggests the possibility of AFH, in particular in a child or young adult with a subcutaneous mass in a limb.

Inclusion of AFH in the differential diagnosis is important so that the patient can undergo the preferred treatment of wide excision as tumors may recur following marginal resection.

Coursey Moreno, C, Martinez, S, Vinson, E, Brigman, B, Dodd, L, Angiomatoid Fibrous Histiocytoma: Novel MR Observations, Pathologic & Clinical Features.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018126.html