Myxoid atypical fibroxanthoma: a previously undescribed variant.
ABSTRACT Atypical fibroxanthomas (AFX) are dermal-based cutaneous tumors typically found in sun-damaged skin of the elderly. Histologic variants include spindle cell, clear cell, osteoid, osteoclastic, chondroid, pigmented, and granular cell. To date, myxoid change in AFX, has not been described.
Four cases were retrieved from the consultation and surgical pathology files of Knoxville Dermatopathology Laboratory, Knoxville, Tennessee during a 4-year period. The clinical and histologic findings were reviewed and Alcian blue/periodic acid-Schiff (PAS) stain and panel of immunohistochemical stains was obtained.
All 4 lesions occurred as solitary lesions in elderly males on the head and neck (2 cases) and upper extremity (2 cases). Histologically all tumors demonstrated a well-circumscribed, cellular lesion centered in the dermis and composed of a mix of atypical pleomorphic and spindle cells in a prominent myxomatous background. A junctional component was absent and the tumors did not arise from the epidermis or adnexal structures. Subcutaneous involvement was absent in all cases. Tumor cells were negative for melanocytic and epithelial markers. Positive staining was noted with CD10 (3/4 cases) and vimentin (4/4 cases).
Myxoid change in AFX is rare and previously undescribed in the English literature. Myxoid change may be a prominent finding in benign and malignant cutaneous tumors and awareness of this variant of AFX will avoid misdiagnosis.
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ABSTRACT: Atypical fibroxanthoma (AFX) is a cutaneous neoplasm of uncertain etiology that develops on sun-exposed regions of elderly males. It is widely considered to act indolently, despite its highly malignant cytologic features. Reports of metastatic AFX are very rare, and recurrence is uncommon. We report a case of recurrent AFX exhibiting a pattern of satellite metastasis followed by evidence of regional lymph node metastasis. A 76-year-old male with prior occupational and therapeutic radiation exposure and numerous squamous cell carcinomas had AFX of the left vertex scalp limited to the dermis completely removed by micrographic surgery. Twenty months later, multiple lesions appeared at the site of previous surgery. Imaging revealed no metastases or calvarial involvement. Wide local excision showed multiple well-defined nodules involving dermis and subcutis. The primary and recurrent neoplasms were similar and composed of pleomorphic epithelioid and spindled cells with marked nuclear atypia, hyperchromasia and mitotic activity. Immunohistochemistry was positive for CD10, procollagen1 and vimentin and negative for cytokeratins AE1/AE3, cytokeratins 5/6, 34βE12, MNF116, p63 CD31, Mart1, smooth muscle actin, desmin, S100 and CD34. Forty-eight months after removal of the primary, left intraparotid and posterior triangle lymph nodes are suspected to be involved by metastasis using clinical and positron emission tomography/ computed tomography examinations.Journal of Cutaneous Pathology 11/2014; 42(1). DOI:10.1111/cup.12447 · 1.56 Impact Factor
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ABSTRACT: Atypical fibroxanthoma (AFX) is an uncommon cutaneous neoplasm that usually presents as a rapidly-growing nodule in sun-exposed sites in elderly patients. Despite its highly atypical histological appearance it is almost always associated with innocuous clinical behaviour. AFX is now generally regarded as the superficial counterpart of undifferentiated pleomorphic sarcoma (so-called malignant fibrous histiocytoma [MFH]). The former lesion is associated with an excellent prognosis in view of its small size, superficial location, and amenability to complete excision. Because a distinction between AFX and MFH requires assessment of the depth of invasion, a definitive diagnosis of AFX cannot be made on the basis of shallow biopsies. Other cutaneous tumours, including sarcomatoid squamous cell carcinoma (SCC) and spindle-cell melanoma, may have a histologic appearance that is indistinguishable from AFX on haematoxylin–eosin stained slides; immunochemical stains are therefore mandatory in the pathologic evaluation of such cases. There are no currently-known specific immunohistochemical markers (including CD10) which are diagnostic of AFX, and it remains a diagnosis of exclusion. Recent studies have highlighted the importance of other markers, such as high molecular-weight keratins (e.g., CK5/6, 34BE12, and MNF116) and p63 in the diagnosis of sarcomatoid squamous cell carcinoma; that tumour may fail to label for other keratin proteins. Recently, uncommon variants of AFX have been described that broaden its histological differential diagnosis.Diagnostic Histopathology 09/2010; 16(9):401-408. DOI:10.1016/j.mpdhp.2010.06.007
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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.Annals of diagnostic pathology 09/2013; 17(6). DOI:10.1016/j.anndiagpath.2013.08.004 · 1.11 Impact Factor