Cutaneous atypical fibroxanthoma with osteoclast‐like giant cell: A rare phenomenon

Abstract

Atypical fibroxanthoma (AFX) with osteoclast‐like giant cells is a rare entity. We present the case of an elderly woman who presented with a pink–purple dome‐shaped nodule with central hyperkeratotic crust. Biopsy revealed a cellular, dermal‐based tumor comprised of spindle, oval, and osteoclast‐like giant cells with pleomorphism. The immunohistochemistry profile supported a diagnosis of AFX with osteoclast‐like giant cells. We performed a literature review through PubMed and Google Scholar for AFX with osteoclast‐like giant cell formation and found 16 previously reported cases. We aim to provide a review and discuss features of these cases. We also discuss the pathogenesis of these osteoclast‐like cells as well as potential pitfalls in diagnosis.

Cutaneous Atypical Fibroxanthoma With Osteoclast-Like Giant Cell: A Rare but Diagnostic Pitfall

“…1,4 CD68 and smooth muscle actin staining can be variable. 1,2,4 Although classic AFXs show negative staining for S100, 1,2,4 the osteoclast-like giant cells variant shows positive S100 expression. 10…”

“…1,4 CD68 and smooth muscle actin staining can be variable. 1,2,4 Although classic AFXs show negative staining for S100, 1,2,4 the osteoclast-like giant cells variant shows positive S100 expression. 10 Osteoclast-like multinucleated giant cells predominance is unusual and can be encountered in malignant cutaneous neoplasms including sarcomatoid squamous cell carcinoma, melanoma, leiomyosarcoma, and undifferentiated pleomorphic sarcoma (UPS)/pleomorphic dermal sarcoma (PDS).…”

“…18 A broad immunostain panel including melanoma markers (eg, SOX10, Melan A, and S100) and keratinocyte markers (eg, AE1/AE3, MNF116, P63, and P40) aids in ruling out melanoma and squamous cell carcinoma. 1,2,4 However, it is important to note that numerous Langerhans cells and osteoclast-like giant cells may stain positive for S100. 1,2,10 Strong desmin or h-caldesmon staining suggests a diagnosis of leiomyosarcoma.…”

“…1,2,4 However, it is important to note that numerous Langerhans cells and osteoclast-like giant cells may stain positive for S100. 1,2,10 Strong desmin or h-caldesmon staining suggests a diagnosis of leiomyosarcoma. CD10 might be the only positive stain in AFXs.…”

“…1 The histologic variant of AFX with osteoclast-like giant cells has been rarely documented, with only 17 previously reported cases in the literature. 2 Although AFX tumors may demonstrate striking histological features, most cases have a favorable prognosis with less than 5% local recurrence if not completely excised. 1,3 Here, we present a case of AFX with osteoclast-like giant cells in a 77-year-old man who presented with a new, enlarging erythematous nodule on the parietal scalp.…”