Raquel S. Simón

Does eccrine hidrocystoma exist

To the Editor, We have read the interesting paper about the cysts of the sweat glands, by de Viragh et al., which appeared on the April 1997 issue of the Journal of Cutaneous Pathology, and we agree with the most part of it. We have recently reviewed the adnexal cysts in our files (2). Concerning the cysts of the sweat glands, we concluded, like de Viragh et al. (1), that some of the cases that had previously been diagnosed in our laboratory as eccrine hidrocystoma (on the basis of an unilocular and dilated cyst devoid of papillary infoldings, and a cyst wall composed of two layers of cuboidal cells) were actually apocrine cysts. We arrived at this conclusion by the simple method of observing the less typical areas of the cyst wall of the histologically most typical cases of apocrine cystadenoma, where such a cytological structure was frequently seen. In almost every case, this was also confirmed by the finding of more typical areas, with the decapitation secretion pattern, when serial sections were performed. The rest of our cases that had previously been diagnosed as eccrine hidrocystoma consisted also of a unilocular and dilated cyst devoid of papillary infoldings, but with a wall composed of a squamous epithelium with 2-8 layers of nucleated cells and a cuticle-like horny layer. This cornified layer was not an outstanding feature, because it was either chromophobe for both hematoxilin and eosin or slightly eosinophilic. It was better evidenced by semi-closing the diaphragm of the microscope, which disclosed its refringence. the inner surface of this epithelium was usually smooth, but was sometimes undulating and corrugated in areas, and, in almost every case serial sections disclosed a corrugated area. In summary, these cases were solitary steatocystomas. Neither sebaceous lobules nor solitary sebocytes were usually found in relation to the wall of those cysts; but we have known, since 1982, that the presence of sebocytes is not an essential requisite for the histological diagnosis of steatocystoma to be made (3); this was later confirmed by other authors (4—6). In our review, we also demonstrated that undulation of the inner surface of the cyst wall is not a requisite for the diagnosis. The least common denominator for steatocystoma is a squamous epithelium with 2-8 layers of nucleated cells and a cuticle-like horny layer, either smooth or corrugated (7); i.e. a similar structure to that of the wall of the sebaceous duct(2, 7, 8). All the above described features of a steatocystoma wall can be seen in the second row (E6) of photomicrographs of Fig. 1 of the paper of de Viragh et al. (1). This row illustrates their second group of tumors formed by cases that were considered by the authors to be cysts of the eccrine duct. It is in the photomicrographs corresponding to K8 and Kl/5/10/14 immunostaining of case E6 in Fig. 1 that the cuticle-like horny layer can be clearly seen. It is different from the cuticular border of the luminal cells of the sweat duct, because the latter is merely a more hyaline area of the cytoplasm and not a layer of cornified cells. In consequence, and according to both our own investigation and our interpretation of that of de Viragh et al., a true eccrine hidrocystoma is either a non-existent or a very rare entity. The cases previously diagnosed by de Viragh et al. as eccrine hidrocystoma were either apocrine cystadenoma, apocrine hydrocystoma or steatocystoma, and our cases with the same previous diagnosis were either apocrine cystadenoma or steatocystoma. Formerly, Sangueza denied the existence of eccrine hydrocystoma (9), and this thesis is also supported by Requenaetal. (10). Does an eccrine unit never form a cystic dilation? Nobody has ever found a cyst with eccrine secretory differentiation. On the contrary, it is not exceptional to see in cutaneous biopsy specimens a microscopically dilated eccrine duct. Imamura found such a feature in 18 of 1323 cutaneous biopsy specimens (11). On the other hand, many of the milia cysts, for example those produced in the dermal types of epidermolysis bullosa, are usually cysts of the eccrine dermal duct with an epidermoid metaplasia of its wall; but the so-called eccrine hidrocystoma is very probably a non-existent entity.

Vein, artery, or arteriole? A decisive question in hypodermal pathology.

1. Lazar AJ, Fletcher CD. Distinctive dermal clear cell mesenchymal neoplasm: clinicopathologic analysis of five cases. Am J Dermatopathol. 2004;26:273–279. 2. McAlhany SJ, LeBoit PE. New observations on the ‘‘distinctive dermal clear cell mesenchymal neoplasm’’ of Lazar and Fletcher. Am J Dermatopathol. 2006;00;229. 3. Gavino AC, Pitha JV, Bakshi NA. Atypical distinctive dermal clear cell mesenchymal neoplasm arising in the scalp. J Cutan Pathol. 2008;35:423–427. 4. Ma CK, Zarbo RJ, Gown AM. Immunohistochemical characterization of atypical fibroxanthoma and dermatofibrosarcoma protuberans. Am J Clin Pathol. 1992;97:478–483. 5. Cai JP, Randall B. HMB-45 expression in a clear cell variant of atypical fibroxanthoma. J Cutan Pathol. 2006;33:186–188. 6. Crowson AN, Carlson-Sweet K, Macinnis C, et al. Clear cell atypical fibroxanthoma:a clinicopathologic study. J Cutan Pathol. 2002;29: 374–381. 7. Lazaro-Santander R, Andres-Gozalbo C, Rodriguez-Pereira C, et al. Clear cell atypical fibroxanthoma. Histopathology. 1999;35: 484–485. 8. Kemmerling R, Dietze O, Müller S, et al. Aspects of the differential diagnosis of clear-cell lesions of the skin in connection with the rare case of a clear-cell atypical fibroxanthoma. Pathol Res Pract. 2009;205: 365–370. 9. Murali R, Palfreeman S. Clear cell atypical fibroxanthoma-report of a case with review of the literature. J Cutan Pathol. 2006;33: 343–348. 10. Patterson JW, Konerding H, Kramer WM. ‘‘Clear cell’’ atypical fibroxanthoma. J Dermatol Surg Oncol. 1987;13:1109–1114. 11. Requena L, Sangueza OP, Sanchez YE, et al. Clear-cell atypical fibroxanthoma: an uncommon histopathologic variant of atypical fibroxanthoma. J Cutan Pathol. 1997;24: 176–182. 12. Suárez-Vilela D, Izquierdo-Garcı́a F, Domı́nguez-Iglesias F, et al. Combined papillated Bowen disease and clear cell atypical fibroxanthoma. Case Rep Dermatol. 2010;7: 69–75.

El nevo melanocítico displásico, 24 años después: existe, pero no es displásico

Antecedentes : nevo melanocitico displasico es un diagnostico histopatologico habitual en la mayor parte de los laboratorios de Anatomia Patologica. Sin embargo, parece no existir un consenso general acerca de los criterios objetivos en los que se basa. Material y metodos : los autores han revisado y resumido con la mayor fidelidad posible las descripciones histopatologicas del nevo displasico en los dos trabajos princeps (de Clark et al y de Elder et al), en seis libros recientes de dermatopatologia y en dos libros monograficos sobre neoplasias melanociticas, todos ellos representativos de las diversas opiniones sobre el tema. Resultado :parece haber unanimidad en que el nevo displasico compuesto es un nevo melanocitico compuesto o intradermico rodeado por un «hombro» juntural; en ese «hombro » los nidos son de forma y tamano variables y de distribucion desordenada; sus celulas tienen amplio citoplasma con melanina pulverulenta; la dermis superficial subyacente muestra fibroplasia, infiltrados linfohistiocitarios y neoangiogenesis. Un nevo displasico juntural es un «hombro sin cabeza». El nevo displasico es una lesion benigna. Las discrepancias se plantean en torno a la displasia melanocitica lentiginosa y a la atipia celular. Conclusiones : los autores consideran que el nevo displasico tal como lo describieron Clark et al debe llamarse nevo de Clark; la variante que describieron Elder et al es un nevo lentiginoso. Otros tipos de nevo melanocitico juntural menos frecuentes son el que los autores llaman tipo clasico (con nidos junturales grandes y redondos) y las fases junturales de los nevos de Reed y de Spitz. El nevo de Clark y el nevo lentiginoso son muy frecuentes y no parecen tener mayor propension a la transformacion maligna que los otros tres tipos. La mayor parte de los melanomas aparecidos en pacientes con nevos displasicos surgen de novo, y, a veces, en relacion, logicamente, con los tipos de nevo juntural y nevo compuesto mas frecuentes: el nevo de Clark y el nevo lentiginoso.

But... Was There Ever a Clark Classification of Melanomas

For the past 40 years, the Clark classification of cutaneous melanoma has been accepted and used by the vast majority of dermatologists and pathologists throughout the world. However,after careful rereading of the most relevant articles by Clark and his collaborators, we can affirm that the classification was only ever of passing validity. Today, the possible morphological differences between one case of cutaneous melanoma and another are of no proven prognostic implication. In addition, the morphological differences that can be found are much more closely related to the different localization that to the tumor itself.

Variaciones cualitativas y cuantitativas de la capa córnea epidérmica: su utilidad diagnóstica

Introduccion en 1978, Ackerman anadio a los tradicionales terminos de hiperqueratosis ortoqueratosica y paraqueratosica tres variedades de la primera: laxa, compacta y laminar. Metodo en este articulo redefinimos y matizamos tales terminos llamando la atencion sobre un aspecto no estudiado anteriormente: la apetencia tintorial de cada una de esas variedades de capa cornea. Resultados la capa cornea laxa, normal o hiperqueratosica es siempre basofila. La cornea compacta, normal, hiperqueratosica o heterotopica muestra dos variantes, una basofila y otra eosinofila. La cornea laminar es siempre eosinofila igual que la cornea paraqueratosica. Conclusiones tomando como base la apetencia tintorial de la capa cornea (basofila o eosinofila) y su estructura (laxa, compacta, laminar o paraqueratosica), se propone un algoritmo con el que efectuar una descripcion objetiva de la capa cornea epidermica de cada biopsia. Se discute la significacion de cada una de esas variedades atendiendo a la localizacion del proceso biopsiado.