Cellular neurothekeoma is a frequent source of diagnostic difficulty. In order to gain more insight into the range of histologic features of cellular neurothekeoma, we examined all cases from our institution, with a focus on describing atypical histologic features. Cases with sufficient histologic material for evaluation were retrieved. Cases were analyzed for demographics, growth pattern, myxoid stroma, cytologic atypia, mitotic rate, perineural invasion, and other histologic features. The 37 patients (16 M; 21 F) had a mean age of 31.0 years (range: 4-89). Tumors involved the head and neck (n ¼ 16), arms (n ¼ 11), trunk and shoulders (n ¼ 8), and foot (n ¼ 2). All cases had at least focal nesting of epithelioid to spindled tumors cells characteristic of cellular neurothekeoma. In many, alternate growth patterns were present and represented the dominant pattern in some. These patterns included fascicular (n ¼ 9), sheet-like (n ¼ 6), and corded (n ¼ 4). Myxoid stroma was present in 14 and was prominent in 5. Cytologic atypia was present in 19 patients, with 3 having severe atypia. Mean mitotic rate was 2.0/mm 2 (range 0-10 per mm 2 ). Neurotropism was seen in four cases. Other unusual features included collagen trapping, giant cells, hemorrhage, lymphocytic cuffing, chondroid stroma, and cellular vacuolization. Cellular neurothekeoma has a wider range of features than is commonly recognized. The presence of nests of epithelioid tumor cells with characteristic cytologic features, no matter how focal, is a clue to the diagnosis. Keywords: atypical cellular neurothekeoma; cellular neurothekeoma; immunohistochemistry Cellular neurothekeoma, formerly considered a nerve sheath tumor, is a dermal neoplasm of presumed fibrohistiocytic lineage. 1-3 They typically occur on the head, neck, and upper body of young adults, with a slight female predominance. [2][3][4] The classic histology of cellular neurothekeoma is of a dermal-based lesion with a lobular growth pattern that forms nests with a swirling to slightly fascicular growth pattern. The tumor cells are epithelioid to spindled with abundant pale eosinophilic cytoplasm, oval nuclei with pinpoint nucleoli. Although most cellular neurothekeomas display these characteristic histologic features, atypical features have been described, including prominent myxoid stroma, cytologic atypia, infiltrative growth, vascular invasion, perineural invasion, fascicular and plexiform growth patterns, and dense hyalinized stroma. 3-9 When atypical features are present, the diagnosis of cellular neurothekeoma can be challenging. For this reason, cellular neurothekeoma with atypical features is a relatively frequent source of referral to our consultation practice. In order to gain more insight into the range of histologic features of cellular neurothekeoma, we examined a large series from our practice with a focus on describing unusual features. Materials and methodsWe retrieved all cases of cellular neurothekeoma from 1980 to 2012 with sufficient histologic material. We recorded the demo...

In December of 2008, our institution performed a near total face transplant. The patient was monitored for signs of rejection assessed by paired skin and mucosa biopsies. The results of histological review of 120 biopsies collected during the first 4 years posttransplant are discussed. All biopsies were stained with hematoxylin and eosin, periodic acid-Schiff, immunohistochemical and TUNEL assays and graded using the Banff 2007 classification. Grade III rejection was diagnosed clinically at weeks 45 and 66, posttransplant; week 45 was determined as folliculitis while the erythema episode at week 66 confirmed an acute rejection (AR) that required hospitalization. The mucosa frequently showed interface inflammation without clinical signs of rejection and was not present in skin biopsies. In all, 34 of the 45 mucosal biopsies (75%) showed these interface changes. Clinical symptoms concurred with skin pathology in two grade III rejections. The mucosa showed histologic signs of rejection more frequently, which may indicate: increased mucosal sensitivity to rejection, a different type or subtype of AR that is specific to the mucosa, or a nonspecific process such as a drug effect. With more data and world experience, the diagnosis of face transplant rejection will be better defined and the Banff classification enhanced.

Both topical tacrolimus and clobetasol were effective in treating episodes of acute rejection, and the best outcomes were achieved when their application was initiated after systemic immunosuppression. Topical tacrolimus proved to be a preferable adjunct agent to the systemic therapy by preventing both the local and systemic complications.

A conservative immunohistochemical panel including PAX-8, vimentin and CEA allow for easy distinction of CCRCC from hidradenoma, whereas napsin A added no additional value.

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