Pseudogranulomatous Spitz nevus: a variant of Spitz nevus with heavy inflammatory infiltrate mimicking a granulomatous dermatitis.

Spitz nevus is a benign melanocytic proliferation that shows relatively characteristic clinicopathologic features. Despite this, Spitz nevus is clinically confused with many other lesions, and histopathologically it is sometimes difficult to distinguish it from melanoma. However, Spitz nevus rarely causes differential diagnostic problems with granulomatous dermatitis. This article describes an 8-year-old girl who presented with a nodule on her right arm, a clinical appearance of a pyogenic granuloma. Histopathologically, there was a dermal lesion composed of aggregates of large epithelioid cells surrounded by a heavy inflammatory infiltrate, mimicking a sarcoid-like granulomatous dermatitis. Immunohistochemistry showed epithelioid cells with strong nuclear and cytoplasmic staining with S-100 protein, thus establishing the diagnosis of a melanocytic tumor. The heavy T-cell lymphocytic infiltrate that accompanies the large epithelioid cells caused its granulomatous appearance. Molecular assessment showed H27H mutation in the HRAS gene. We suggest the term 'pseudogranulomatous' for this variant of Spitz nevus because it indicates that the lesion is not authentically granulomatous and simply mimics a granulomatous dermatitis.

Morphological keys in the differential diagnosis of bladder inverted papilloma. Study of two types, trabecular and glandular.

OBJECTIVE: Inverted papilloma of the urinary bladder is an uncommon urothelial neoplasm that may be specially difficult to distinguish from urothelial carcinoma. METHODS: Two patients with obstructive symptoms and hematuria have been studied. In the transurethral resection, accidentally, one showed a papillary lesion in the context of nodular hyperplasia of the prostate, where as the other showed a polypoid tumor of the urinary bladder RESULTS: Histologically, in both cases, a bladder inverted papilloma was demonstrated, originating from the surface transitional epithelium. Basal cells exhibited peripheral palisading pattern in the trabecular form. In the glandular type, Dogiel or umbrella cells into the gland-like structures, were recognized. Immunohistochemical stains for p53 and Ki-67 were negative. Umbrella cells were positive for cytokeratin 20. CONCLUSIONS: Two cases of bladder inverted papilloma with relevant morphological aspects are presented, which we consider useful for the differential diagnosis with urothelial carcinoma.

Claves morfológicas en el diagnóstico diferencial del papiloma invertido vesical. Estudio de dos variedades, trabecular y glandular / Morphological keys in the differential diagnosis of bladder inverted papilloma. Study of two types, trabecular and glandular

OBJETIVO: El papiloma invertido vesical es una neoplasia urotelial poco frecuente que plantea dificultades en el diagnóstico con el carcinoma urotelial. MÉTODO: Se presentan dos pacientes, con manifestaciones clínicas de obstrucción y hematuria. En la resección transuretral, uno presentó lesión papilar en el contexto de una hiperplasia nodular prostática, mientras que en el otro se demostró una tumoración vesical polipoide. RESULTADOS: Morfológicamente en ambos casos se puso de manifiesto un papiloma invertido vesical de origen en el urotelio superficial. En la variedad trabecular, las células basales se disponían con patrón de empalizada periférica. En el tipo glandular se reconocían, dentro de las áreas seudoglandulares, células superficiales o de Dogiel. Tinciones inmunohistoquímicas para p53 y Ki-67 resultaron negativas. Las células superficiales fueron positivas con citoqueratina 20. CONCLUSIÓN: Se estudian dos variedades de papiloma invertido vesical, con aspectos morfológicos relevantes en el diagnóstico diferencial con el carcinoma urotelial (AU)

OBJECTIVE: Inverted papilloma of the urinary bladder is an uncommon urothelial neoplasm that may be specially difficult to distinguish from urothelial carcinoma. METHODS: Two patients with obstructive symptoms and hematuria have been studied. In the transurethral resection, accidentally, one showed a papillary lesion in the context of nodular hyperplasia of the prostate, where as the other showed a polypoid tumor of the urinary bladder. RESULTS: Histologically, in both cases, a bladder inverted papilloma was demonstrated, originating from the surface transitional epithelium. Basal cells exhibited peripheral palisading pattern in the trabecular form. In the glandular type, Dogiel or umbrella cells into the gland-like structures, were recognized. Immunohistochemical stains for p53 and Ki-67 were negative. Umbrella cells were positive for cytokeratin 20. CONCLUSIONS: Two cases of bladder inverted papilloma with relevant morphological aspects are presented, which we consider useful for the differential diagnosis with urothelial carcinoma (AU)

Signet ring cell melanocytic nevus: report of a case over trichilemmal cyst and review of the literature.

Different melanocytic nevi have been reported as being associated with dermal cysts. Signet ring cell melanocytic nevus is a rare variant of melanocytic nevus characterized by cells with signet ring morphology within a common melanocytic nevus. This article describes an exceptional case of melanocytic nevus composed exclusively of signet ring cells over a trichilemmal cyst. Histologically, above the cyst, there was a small, symmetrical and sharply demarcated lesion showing a compound proliferation of small, round, monomorphous cells with signet ring morphology. Immunohistochemically, signet ring cells were negative for cytokeratin AE1/3, leukocyte common antigen, HMB-45, and CD34. Occasionally, isolated signet ring cells were positive for S-100 and melan A. Melanocytic nevus composed of signet ring cells should raise the differential diagnosis with other cutaneous tumors exhibiting signet ring cells. Previous cases of this entity reported in the literature are also reviewed.

Tumor linfoepitelial benigno cutáneo. Estudio de un caso congénito con diferenciación ductal / Benign lymphoepithelial tumor of the skin. Study of a congenital case with ductal differentiation

El tumor linfoepitelial benigno cutáneo es una neoplasiaanexial poco frecuente que se caracteriza por una proliferacióncelular bifásica, epitelial y linfoide, con capacidad dediferenciación folicular o ductal. Describimos un nuevocaso de este peculiar tumor que se presentó en un varónrecién nacido. El estudio histológico e inmunohistoquímicodemostró evidencia de diferenciación ductal. Presentamosel primer caso que se conoce de tumor linfoepitelial benignocutáneo congénito de origen glandular ecrino

Benign lymphoepithelial tumor of the skin is a rareadnexal neoplasm that is characterized by a cellular biphasicproliferation: A new case of this peculiar tumor in a newbornmale is reported. Ductal differentiation was revealedby histology and inmmunohistochemistry. A careful examinationof the current literature was not able to found reportsabout cases of congenital benign eccrine lymphoepithelialtumor of the skin