Context. —Several aspects of sweat gland carcinomas (incidence, classification, diagnosis, and behavior) have not been definitively clarified and need to be studied further. Objective. —The clinicopathologic findings of a large series of sweat gland carcinomas, collected during a period of 15 years, are presented. Methods. —Sixty sweat gland carcinomas (41 porocarcinomas, 3 syringomatous carcinomas, 8 ductal carcinomas, 5 adenoid cystic carcinomas, and 3 mucinous carcinomas) were analyzed histologically and immunohistochemically. Results. —Porocarcinomas were composed of eosinophilic and clear atypical cells arranged in solid-cystic lobular masses. These tumors were divided into 2 subgroups: horizontal porocarcinomas, showing a prominent intraepidermal component, and nodular porocarcinomas, which demonstrated predominant nodular growth. Syringomatous carcinomas presented keratinizing and nonkeratinizing cysts, dilated tubules (sometimes with a “tadpole” appearance), small neoplastic ducts, solid islands, and cellular cords. Ductal carcinomas were characterized by a prominent formation of tubules, solid islands, and cellular cords. Adenoid cystic carcinomas presented a characteristic pattern, showing basaloid monomorphous cells with moderately atypical nuclei, arranged in cribriform or solid islands and in tubular structures. Mucinous carcinomas were composed of moderately atypical cells with eosinophilic vacuolated cytoplasm, forming solid and cystic islands floating in large mucin pools. Immunohistochemically, cytokeratin was found in neoplastic cells in all cases, carcinoembryonic antigen was detected in 73% of cases, and actin-positive (myoepithelial) cells were not found. Conclusions. —Although numerous studies have been published in recent years, the histologic features, histogenesis, and classification of sweat gland carcinomas still remain controversial and need to be clarified by further studies.

• Intratumoral and peritumoral infiltration of T-zone histiocytes, mainly of mature Langerhans cells, was investigated in 88 patients with squamous cell carcinoma of the larynx by immunohistochemical methods using polyclonal antibodies against S100 protein and lysozyme. Granulocytic and lymphoid inflammatory infiltration and its relationship to the presence of Langerhans cells were also evaluated. Langerhans cells were present within the cancer tissues and showed a relationship with lymphoid infiltrate. No significant correlation was present among the density of Langerhans cells and the site of neoplastic growth (supraglottic or subglottic), granulocytic inflammatory infiltration, histological tumor grade, or clinical stage. Patients with high or intermediate density of Langerhans cells survived longer than those with low density (mean survival, 61%, 62%, and 0%, respectively). The number of Langerhans cells was relevant in patients with evident infiltration of lymphocytes and plasma cells, according to their ability to present antigens to sensitized T cells. Our results indicate that the presence of high or intermediate density of Langerhans cells and of marked lymphoid inflammation may be considered favorable prognostic factors for patients with squamous cell carcinoma of the larynx. (Arch Otolaryngol Head Neck Surg. 1991;117:1007-1010)

We tested the relevance of clinical information in the histopathologic evaluation of melanocytic skin neoplasm (MSN). Histopathologic specimens from 99 clinically atypical MSN were circulated among ten histopathologists; each case had clinical information available in a database with a five-step procedure (no information; age/sex/location; clinical diagnosis; clinical image; dermoscopic image); each step had a histopathologic diagnosis (D1 through D5); each diagnostic step had a level of diagnostic confidence (LDC) ranging from 1 (no diagnostic certainty) to 5 (absolute diagnostic certainty). The comparison of the LDC was employed with an analysis of variance (ANOVA) for repeated measures. In D1 (no information), 36/99 cases (36.3%) had unanimous diagnosis; in D5 (full information available), 51/99 cases (51.5%) had unanimous diagnosis (p for difference between proportions <0.001). The observer agreement expressed as kappa increased significantly from D1 to D5. The mean LDC linearly increased for each observer from D1 through D5 (p for linear trend <0.001). On average, each histopathologist changed his initial diagnosis in 7 cases (range: 2–23). Most diagnostic changes were in D2 (age/sex/location). The histopathologic criteria for the diagnosis of MSN can work as such, but the final histopathologic diagnosis is a clinically-aided interpretation. Clinical data sometimes reverse the initial histopathologic evaluation.