Atypical Fibroxanthoma: A Histological and Immunohistochemical Review of 171 Cases

Article (PDF Available)inThe American Journal of dermatopathology 32(6):533-40 · August 2010with94 Reads
DOI: 10.1097/DAD.0b013e3181c80b97 · Source: PubMed
The clinical and histological features of 171 atypical fibroxanthomas (AFX) from a single institution in Western Australia are outlined. This area experiences high levels of solar radiation, and all assessable biopsies showed solar elastosis. Patients were aged between 41 and 97 years (median age 74), with 76% of tumors occurring in men (male to female ratio approximately 3 to 1). Most tumors were small, with a median diameter of 10 mm and a range of 4-35 mm. Only 5% exceeded 20 mm in diameter. Most AFX were well-circumscribed dermal lesions, with limited invasion of subcutis in a minority. Histological variants identified included keloidal (n = 8), clear cell (n = 3), and granular cell (n = 3), plaque like (n = 4), and myxoid (n = 1). Bland cytological appearances (spindle cell nonpleomorphic AFX) were noted in 5 tumors, with osteoclast-like giant cells in 2. Features suggesting regression were present in 22 cases. Two cases recurred locally, none metastasized. No tumors expressed melanocytic or epithelial markers. Seventy-four percent of cases expressed smooth muscle actin, typically strongly and diffusely. No AFX stained with desmin. Only 1 of 50 cases was CD117 positive. In conclusion, AFX may show a wide range of histological appearances, and a panel of immunohistochemical markers is essential to make the correct diagnosis. Histological mimics, such as poorly differentiated squamous cell carcinoma, must be carefully excluded. Specific diagnosis is important because there seems to be a very low risk of recurrence or metastasis despite the frequently alarming histology.


    • "Absent immunostaining for cytokeratins, S100 and HMB45 are helpful in excluding both carcinoma and melanoma. A histiocytic/macrophage marker (CD68) is positive in more than half of all AFX cases [1,456 . The initial diagnosis was malignant mesenchymal neoplasm suggestive of low level sarcoma , requiring IHC analysis. "
    [Show abstract] [Hide abstract] ABSTRACT: Atypical fibroxanthoma (AFX) is a rare skin neoplasm of low-grade malignancy and fibroblastic origin. AFX is a curable cutaneous disease and the diagnosis depends on knowledge of its clinical and histological features and combined immunohistochemistry markers. This study presents a case of a male patient, aged 90 years, presented with painless skin lesion in his ear. The lesion had been growing progressively for 2 months, measured ∼1.5 cm, ulcerated, fixed and firm. After a biopsy, the patient underwent a complete resection with adequate surgical margins and showed favorable evolution without complications or recurrence. The histopathological evaluation showed a poorly circumscribed ulcerated dermal nodule, mesenchymal proliferation, with pleomorphic spindle cells. There was infiltration of the deep dermis and subcutis, showing malignant features, but there was no invasion of cartilage. The immunohistochemical analysis confirmed the diagnosis of AFX. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2015.
    Full-text · Article · Mar 2015
    • "The tumors are frequently ulcerated and are characterized by sheets and fascicles of pleomorphic epithelioid and spindle cells including multinucleated forms in varying proportions. Mitotic activity is brisk including atypical and often bizarre forms1239]. With expression of CD68, CD10, and CD99 the immunohistochemical profile is of no discriminatory value and additional negative staining for multiple cytokeratins, desmin, CD34, and S100 is required to exclude, in particular , melanoma, carcinoma, leiomyosarcoma and angiosarcoma [9,12131415. "
    [Show abstract] [Hide abstract] ABSTRACT: Atypical fibroxanthoma and pleomorphic dermal sarcoma may be difficult to separate from cutaneous angiosarcoma. We aim to study the morphological spectrum of pseudoangiomatous features in these tumors and the value of staining for endothelial markers CD31, CD34, FLI1, and ERG. Eleven atypical fibroxanthomas and 3 pleomorphic dermal sarcomas were identified. All tumors arose on sun-damaged skin of elderly men. Atypical fibroxanthomas were nodular and confined to the dermis, whereas pleomorphic dermal sarcoma invaded into underlying fascia. All tumors were composed of pleomorphic epithelioid and spindle cells showing blood-filled spaces and intratumoral hemorrhage. Intracytoplasmic vacuoles (n = 4), hemosiderin deposition (n = 2), and keloidal stromal change (n = 1) were also noted. Immunohistochemically, CD31 was expressed in 43% of cases, FLI1 in 79% and smooth muscle actin in 50%. Staining for CD34, ERG, S100, HMB-45, desmin, p63 and cytokeratins was negative. Follow up (median, 43.1 months; range 1-100), available for 10 patients, showed no adverse outcome. Pseudoangiomatous features and aberrant expression of CD31 and FLI1 in atypical fibroxanthoma and pleomorphic dermal sarcoma may lead to an erroneous diagnosis of cutaneous angiosarcoma. Negativity for CD34 and ERG, in particular, is a reliable differentiating feature in this setting.
    Article · Sep 2013
  • [Show abstract] [Hide abstract] ABSTRACT: Luzar B & Calonje E (2010) Histopathology56, 148–165 Cutaneous fibrohistiocytic tumours – an update The term ‘fibrohistiocytic’ tumour is a descriptive designation without histogenetic connotation for a group of heterogeneous lesions that share morphological features of histiocytes and fibroblasts on light microscopy. However, over the years it has become apparent that many so-called ‘fibrohistiocytic’ tumours are largely composed of relatively undifferentiated mesenchymal cells, but can also show areas of myofibroblastic differentiation. This review focuses on the clinical and histological features as well as differential diagnosis of so-called fibrohistiocytic tumours. Special emphasis is given to more recently described histological variants of fibrous histiocytoma, e.g. cellular, epithelioid, aneurysmal and atypical fibrous histiocytoma, to angiomatous and plexiform fibrous histocytoma (plexiform fibrohistiocytic tumour), lesions that are not true variants of fibrous histiocytomas but have erroneously been designated such, and to atypical fibroxanthoma. The literature on metastasizing fibrous histiocytoma is also reviewed.
    Full-text · Article · Jan 2010
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