Giant aneurysmal benign fibrous histiocytoma (dermatofibroma)

Giant thigh hemosiderotic/aneurysmal dermatofibroma: Case report with radiologic-pathologic correlation

Hemosiderotic/aneurysmal variant of dermatofibroma (DF) is infrequent and may be misdiagnosed with malignant lesions. We report the case of a giant (7.6cm) subcutaneous hemosiderotic/aneurysmal DF (H/ADF) of the thigh in a 53-year-old female patient. Internal arterial and venous hypervascularity was seen by spectral Doppler ultrasound. Magnetic resonance image showed a discrete homogeneous hypointense in T1-weighted images (WI) and T2-WI mass, with hyperintense areas in fat-suppressed T2-WI. The histology revealed a monotonous fusocelular proliferation without atypia, positive for CD163, factor XIIIa and CD10. Widely distributed hemosiderin pigment and two blood-filled pseudovascular spaces lacking endothelial lining were present. H/ADF was diagnosed. The mass was removed but surgical margins were affected. The patient did not present local relapse or distant metastasis. H/ADF are unusual cutaneous soft tissue tumours that can be clinically, radiologically and histopathologically confused with malignant lesions such as melanomas, vascular lesions or sarcomas, especially in giant cases.

Angiomatoid Fibrous Histiocytoma With ALK Expression in an Unusual Location and Age Group

Angiomatoid fibrous histiocytoma (AFH) is a relatively rare soft tissue tumor of intermediate malignant potential, occurring most commonly in young adults, with a recognized propensity for local recurrence and occasional metastasis. A case of AFH occurring on the finger of a 60-year-old man is described in which the unusual location and age group for this entity raised the original wrong diagnosis of an aneurysmal and cellular fibrous histiocytoma. Further workup demonstrated an EWSR1-CREB1 translocation, confirming the correct diagnosis of AFH. Strong anaplastic lymphoma kinase (ALK) expression using the antibody clone D5F3 was demonstrated in our case on immunohistochemistry, which is in concordance with recent findings of anaplastic lymphoma kinase positivity with this antibody in the majority of AFHs.

[Angiomatoid fibrous histiocytoma: a literature review and a report of two cases]

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor of intermediate malignancy potential, which predominantly affects children and young adults. This paper describes two cases of AFH, as well as a review of literature during 1979 to 2021. It gives data on the epidemiology, clinical features, diagnosis, and genetic characteristics of AFH.