Spotty skin pigmentation and multiple blue naevi as cutaneous markers for spinal melanotic schwannoma.

Spinal melanotic schwannomas are rare spinal tumours with a very poor prognosis in terms of mortality due to difficulty in complete resection and local recurrences. A 67-year-old man presented with acute onset progressive paraparesis for 2 weeks. The patient also had spotty skin pigmentations (blue naevi) in his right lateral thigh. MRI revealed an intradural extramedullary enhancing lesion in the lower thoracic cord level. With a preoperative diagnosis of simple nerve sheath tumour excision was planned. At laminotomy, an infiltrating "en plaque" like lesion reaching up to mid and upper thoracic cord level was identified and excision was carried out. Postoperative histopathology was unique with the identification of melanin and presence of epitheloid cells, with the additional detection of psammoma bodies and adipose-like cells. Melanotic schwannomas though rare and carry poor prognosis must be borne in mind in patients with spotty skin pigmentation and acute onset limb weakness.

Melanocytic "ball-in-mitts" and "microalveolar structures" and their role in the development of cellular blue nevi.

To test the hypothesis of whether cellular blue nevi (CBN) may originate from "ordinary" compound and dermal nevi, a total of 275 melanocytic nevi including 59 CBN, 34 ordinary blue nevi, 87 combined nevi (including 43 so-called clonal nevi), 35 deep penetrating nevi, and 60 ordinary compound and dermal nevi (30 of each) were studied for the presence of so-called ball-in-mitts and microalveolar structures. A ball-in-mitts structure was defined as a single centrally placed melanocyte with a round to oval nucleus (the "ball" cell) and a clear, dusty, or pigmented cytoplasm encircled by a single dendritic cell (the "mitt" cell) with an oval to spindle-shaped nucleus and slender bipolar processes containing melanin and surrounding at least one fourth of the ball's diameter. A microalveolar structure was defined as a group of 2 to 10 centrally placed melanocytes with round to oval nuclei and clear, dusty, or pigmented cytoplasm (balls) surrounded by one or more cells (mitts) with spindle-shaped nuclei and slender bipolar processes containing melanin. Microscopically, ball-in-mitt and microalveolar structures were detected in all types of nevi studied, with the highest incidence in combined nevi (82%), CBN (76%), and ordinary "nonblue" nevi (73%). In CBN, ball-in-mitts and microalveolar structures tended to be located in the deeper portion of the lesions, whereas in ordinary nonblue nevi, they were most often found superficially, just below the epidermis; in clonal nevi, these structures were often confined to the "clonal" parts. Immunohistochemically, ball-in-mitts and microalveolar structures were positive for HMB45. Ultrastructurally, the balls tended to have round to oval nuclei, whereas the mitts possessed oval, elongated to spindled nuclei. Melanosomes were found in various stages in the cells of both structures. The cytoplasm of the mitts typically formed elongated polar processes, sometimes with club-like widenings at the ends, completely or partially encircling the balls. In the microalveolar structures, the adjacent cells forming the mitts surrounded the ball cells like a chain. Our study suggests that some or even most cases of CBN may evolve from ordinary nonblue nevi. This process may involve several steps and is probably reflected by the appearances of combined nevi, deep penetrating nevi, and CBN. These nevi often show a morphological overlap, and ball-in-mitts and microalveolar structures found in various stages of their development seem to greatly account for this overlap.

Nevo azul en placa / Plaque-type blue nevus

El nevo azul en placa o nevo azul agminado es una lesión melanocítica formada por la agrupación de múltiples lesiones de pigmentación azulada en un área bien delimitada. Presentamos el caso de un hombre de 22 años con un nevo azul en placa en el hombro derecho, que desarrolló tres nódulos profundos. (AU)

Displasia nodular pigmentada suprarrenal bilateral y síndrome de Carney. A propósito de un caso / Primary Pigmented Nodular Adrenocortical Disease and Carney syndrome. A case report

La displasia nodular pigmentada bilateral suprarrenal (DNPBS) es una forma peculiar e infrecuente de aparición del síndrome de Cushing ACTH-independiente. Se presenta con autonomía de las glándulas suprarrenales y displasia suprarrenal bilateral con características histológicas de benignidad. La suprarrenalectomía bilateral es el único tratamiento curativo para esta enfermedad. Se presenta el caso de una mujer de 31 años con DNPBS en la que destaca el inicio relativamente tardío de esta enfermedad y que justifica el aspecto micronodular en el estudio patológico, en contra de la clásica descripción de la DNPBS. Se estudia la posible asociación con el síndrome de Carney (mixomas, lesiones cutáneas hiperpigmentadas e hiperactividad endocrina), del cual la paciente presenta dos elementos: DNPBS y efélides, aunque el estudio familiar es negativo. Se revisa el diagnóstico diferencial de la enfermedad suprarrenal nodular, la DNPBS y el síndrome de Carney (AU)

Fibroblast-dependent induction of a murine skin lesion with similarity to human common blue nevus.

In an attempt to define epithelial-mesenchymal interactions in skin appendage formation, we have been studying a nude mouse grafting model that permits the combination of heterotypic and heterochronic epithelial and mesenchymal cells. In this study using neonatal hair bud cells combined with various mesenchymal cell preparations, we show that one can regenerate near-complete skin with intact epidermal and dermal layers plus mature hair follicles. It was determined that the character of the resulting regenerated skin could be manipulated as a function of the specific mesenchymal component. Lack of dermal cells resulted in a scar, whereas inclusion of a suspension of dissociated total dermal cells resulted in near-complete skin regeneration, and in the presence of follicular papilla fibroblasts (both hair-inductive and non-hair-inductive) or NIH3T3 fibroblasts, the reconstitution had similarity to the common blue nevus. The results indicate that 1) a stimulant of human common blue nevus can be produced in an animal model, 2) the underlying disorder of the lesion in mice appears to be entirely dermal in origin, arising independent of the epidermal component, and 3) complex dermal cell interactions involving lesion-initiative and lesion-suppressive activities underlie the pathogenesis. This experimental system will serve as a valuable tool in elucidating cutaneous dermal-epidermal signals in normal skin as well as the alteration of these signals in malformations such as the hamartoma described here.

Primary orbital melanomas.

PURPOSE: Primary orbital melanomas are rare tumors with a poorly defined biologic course. Most recorded experiences concern single case reports. The authors evaluated the applicability of several of the histopathologic prognostic indicators used for uveal melanomas to a series of primary orbital melanomas with known clinical follow-up. METHODS: Twenty-one primary orbital melanomas, each with at least a 1-year follow-up after diagnosis, were evaluated for (1) modified Callender cell type, (2) mitotic count per 40 high-power fields, (3) lymphocyte count (less than versus greater than 100/20 high-power fields), (4) blue nevus component, and (5) largest tumor diameter. RESULTS: All patients for whom race was recorded were white. The mean age at diagnosis was 42 years (range, 15-84 years). There was an associated blue nevus in 19 patients (90 percent), and in 10 patients (47.5 percent) there was some form of congenital melanosis. With a mean follow-up period of 4.5 years (range, 1-13 years), mortality from metastatic tumor occurred in 8 (38 percent) of 21 patients. Of these eight patients, there were liver metastases in seven (88 percent) and brain metastases in one (12 percent). Indicators of poor prognosis were tumors of mixed cell type with high mitotic count and greater patient age with underlying congenital melanosis. CONCLUSION: Most primary orbital melanomas occur in white patients and are associated with blue nevi. These tumors are similar to uveal melanomas with respect to prognostic indicators and pattern of metastasis.