Aneurysmal bone cyst of the temporal bone associated with reversible hemifacial paralysis.

Aneurysmal bone cyst (ABC) is an uncommon lesion of the temporal bone (TB), with only 20 cases reported. Facial paralysis is a rare complication (2 cases); however, no cases have been reported with preoperative reversal of paralysis. We report a 60-year-old man with a history of remote head trauma, who presented with serious otitis media and right hemifacial paralysis, which resolved with nonsurgical therapeutic measures. Magnetic resonance imaging and computed tomography showed a destructive and expansile lesion of the TB. The lesion was surgically removed, and ABC was diagnosed histologically. The patient had an uneventful recovery and demonstrated no recurrence at 1 year of follow-up. This report presents an unusual presentation of ABC in the TB, with a review of the clinical, radiological, pathological, and therapeutic features of this entity.

Actin expression in purely nodular versus nodular-infiltrative basal cell carcinoma.

BACKGROUND: The prognosis of basal cell carcinoma (BCC) correlates with its histological subtype. Actin is a microfilament that contributes to cell motility and invasiveness of cancer cells. Actin has been found to be more prominently expressed in the tumor cells and stroma of the more aggressive BCC subtypes. Here we compare actin expression in purely nodular (N-BCC) versus nodular-infiltrative (NI-BCC) tumors. METHODS: We studied seven cases of N-BCC and 13 cases of NI-BCC with immunohistochemistry for alpha-smooth muscle actin (SMA) and common muscle actin (CMA) within the tumor cells and stroma. A semiquantitative method was used to determine the degree of actin present in the tumor aggregates (on a scale of 0-4). RESULTS: Actin was present in the nodular component of 2/7 (28%) purely N-BCC and 11/13 (85%) mixed NI-BCC (p = 0.001). Actin was present in the infiltrative component of 13/13 (100%) NI-BCC. The average SMA score was 0.57 within the N-BCC compared with 1.77 within the nodular component of NI-BCC (p = 0.04); and 2.46 within the infiltrative component of the NI-BCC. The CMA score was 0.57 within the N-BCC, 1.54 within the nodular component of NI-BCC, and 1.92 within the infiltrative component of the NI-BCC. Actin was not found in the stroma of any of the N-BCC, while it was present in 8/13 (62%) of the NI-BCC (p = 0.0009). CONCLUSIONS: Actin expression is more prominent in the nodular component of mixed NI-BCC when compared with purely N-BCC. This suggests that the nodular components of NI-BCC and N-BCC are different, and that actin expression in the nodular component may be associated with potential invasiveness. This finding may be relevant when examining incompletely sampled nodular BCC.

Melanocytic matricoma: case confirmation of a recently described entity.

BACKGROUND: In 1999, Carlson et al. reported two cases of a matrical neoplasm that recapitulates the bulb of the anagen hair follicle, which they designated as melanocytic matricoma. METHODS: Here we report a similar case in a 78-year-old white male, who presented with a 0.4 cm purple-black firm papule in the left preauricular area. RESULTS: Histologically, the tumor is composed of a dual cell population including admixed epithelial matrical and supramatrical cells with "shadow" cell formation and pigmented dendritic melanocytes. Immunohistochemical studies for cytokeratin highlighted the epithelial component and studies for S-100 protein, HMB-45, and vimentin confirmed the melanocytic component. The differential diagnosis considered includes pigmented variants of pilomatricoma, matrical carcinoma, basal cell carcinoma and malignant melanoma. CONCLUSIONS: The case reported herein is the first confirmation of melanocytic matricoma, a distinctive adnexal neoplasm with characteristic clinical and pathologic features, which differentiate it from pigmented pilomatricoma.