Angiomatoid Fibrous Histiocytoma of Bone: A Calcifying Sclerosing Variant Mimicking Osteosarcoma

Abstract

Angiomatoid fibrous histiocytoma is a neoplasm of uncertain histogenesis, which most commonly arises in the subcutaneous tissue of the extremities of children and young adults. We report the first case of a calcifying sclerosing variant of this entity. This case arose in bone-a site where there has been just 1 previously published case of typical (nonsclerosing/mineralizing) angiomatoid fibrous histiocytoma. The patient presented with the classical paraneoplastic syndrome that can occur with this tumor type and, apart from the described extracellular matrical features, displayed typical histologic features. Due to the rarity of angiomatoid fibrous histiocytoma at this site and the presence of matrical sclerosis/mineralization, this case raised the important differential diagnosis of osteosarcoma, both histologically and radiologically. The diagnosis was confirmed by molecular analysis; fluorescence in situ hybridization for EWSR1 gene disruption, and reverse transcription-polymerase chain reaction using newly designed primers on both frozen and decalcified, paraffin-embedded tissue samples showing an EWSR1-ATF1 translocation. It is important to recognize that this relatively indolent tumor can arise in bone and that it can contain focally mineralized hyalinized sclerotic matrix to avoid making the serious misdiagnosis of high-grade osteosarcoma and administering aggressive systemic chemotherapeutic treatment.

Orthopaedic Case of the Month: A 14-Year-Old Boy With a Medial Thigh Soft Tissue Mass

“…Local recurrence rates vary from 0% to 63% [10,11,[18][19][20]23]. Additionally, paraneoplastic effects generally resolve within weeks to months after surgical resection of the tumor [32]. Ultimately, the low-grade histologic features, rare distant metastases, and low recurrence rates (mainly local) have resulted in the renaming of this rare entity that previously was known as angiomatoid malignant fibrous histiocytoma to AFH.…”

Angiomatoid Fibrous Histiocytoma: The Current Status of Pathology and Genetics

“…6 Other more frequent sites for AFHs are the trunk and head and neck; occurrence in nonsomatic soft tissue sites is rare but increasingly documented, and unusual primary sites include the brain, 7,8 lungs, 7-9 mediastinum, 6,9,10 retroperitoneum, 6 omentum, 11 ovary, 6 vulva, 6 and bone. 9,10 Extrasomatic AFHs also show a higher mean age at presentation (35 years compared with 12-18 years for somatic cases) 6 and tend to be larger neoplasms. 6 Some patients experience systemic symptoms such as pyrexia, anemia, and malaise, 11 suggesting tumoral cytokine production, and this is also thought to be more frequent in extrasomatic AFH.…”

Recurrent Angiomatoid Fibrous Histiocytoma of thigh in a middle aged female: A case report

“…However, occurrence of AFH in non somatic soft tissue sites such as the lung, mediastinum, vulva, retroperitoneum, ovary, pulmonary artery, kidney, and brain [9]. Omentum [10], ovary, vulva, and bone [11] have been documented in the literature. Our index case was seen in 40 years woman with a recurrent thigh mass measuring 6 cm in maximum dimension.…”