Metastatic aneurysmal fibrous histiocytoma in a 20‐year‐old woman: A rare case report with review of the literature and discussion of its genomic features

Abstract

Aneurysmal fibrous histiocytoma is an uncommon variant of cutaneous fibrous histiocytomas with a local recurrence rate of 19%. We present a case of aneurysmal fibrous histiocytoma in a 20‐year‐old female with a regional lymph node metastasis and subsequent satellite nodule. The patient initially presented with a 1‐month history of two palpable nodules in left lower anterior shoulder and left axilla. Needle core biopsies from both lesions revealed an atypical spindle cell neoplasm with a differential diagnosis of aneurysmal fibrous histiocytoma and angiomatoid fibrous histiocytoma. The axillary dissection confirmed a metastatic deposit in 1 out of 22 lymph nodes. At 6 months a satellite nodule arose between the resection scar and the axilla histopathologically demonstrating a cellular spindle cell nodule at the dermis subcutaneous junction with large, blood‐filled pseudovascular spaces lined by histiocytes. The periphery of the lesion showed collagen trapping without a lymphoplasmacytic infiltrate. The lesional cells were diffusely positive for CD10 and focally for CD68 and Illumina RNA fusion panel sequencing was negative. Herein we present this case of metastatic aneurysmal fibrous histiocytoma with review of the literature and discussion of biology, cytogenetic alterations, and differential diagnosis.

Tumor on the left upper arm of a young woman

“…From a histological point of view, in contrast to our case, AD tends to involve superficial tumors that are immunohistologically positive for vimentin and may exhibit focal expression of factor XIIIA, CD68, and SMA 16 . The treatment of choice for AH is complete excision, although in up to 19% of cases recurrence and, in individual cases, metastases can occur 17,18 . As there are currently no uniform recommendations for either AFH or AD regarding safety margins to reduce recurrences or for the necessary follow‐up care, affected patients must be fully educated and informed that prompt dermatological consultations are indicated in the event of new skin changes.…”

“…16 The treatment of choice for AH is complete excision, although in up to 19% of cases recurrence and, in individual cases, metastases can occur. 17,18 As there are currently no uniform recommendations for either AFH or AD regarding safety margins to reduce recurrences or for the necessary follow-up care, affected patients must be fully educated and informed that prompt dermatological consultations are indicated in the event of new skin changes. The case of our patient shows a clear discrepancy between the clinical, anamnestic, and histologic findings.…”

Metastasizing aneurysmal dermatofibroma initially diagnosed as angiosarcoma confirmed by CD63::PRKCD fusion gene detection with nanopore sequencing

“…In contrast, the present case was accompanied by lymph node metastases. Most DFs follow a benign course without metastasis; however, rare metastasizing DFs have been seen 16–19 . Metastatic sites include the lungs, lymph nodes, soft tissues, and liver.…”

A firm purple nodule on a child's abdomen

“…The high rate of recurrence is likely due to incomplete excision of large primary tumors, rather than a biological difference. 5,6 Although a benign entity, AFH can metastasize in exceptional cases (<1%), 7 most commonly to lungs and lymph nodes. 5 Therefore, complete surgical excision is recommended.…”