Benign follicular tumors

Abstract: Benign follicular tumors comprise a large and heterogeneous group of neoplasms that share a common histogenesis and display morphological features resembling one or several portions of the normal hair follicle, or recapitulate part of its embryological development. Most cases present it as clinically nondescript single lesions and essentially of dermatological relevance. Occasionally, however, these lesions be multiple and represent a cutaneous marker of complex syndromes associated with an increased risk of visceral neoplasms. In this article, the authors present the microscopic structure of the normal hair follicle as a basis to understand the type and level of differentiation of the various follicular tumors. The main clinicopathological features and differential diagnosis of benign follicular tumors are then discussed, including dilated pore of Winer, pilar sheath acanthoma, trichoadenoma, trichilemmoma, infundibuloma, proliferating trichilemmal cyst/tumor, trichoblastoma and its variants, pilomatricoma, trichodiscoma/fibrofolliculoma, neurofollicular hamartoma and trichofolliculoma. In addition, the main syndromes presenting with multiple follicular tumors are also discussed, namely Cowden, Birt-Hogg-Dubé, Rombo and Bazex-Dupré-Christol syndromes, as well as multiple tumors of follicular infundibulum (infundibulomatosis) and multiple trichoepitheliomas. Although the diagnosis of follicular tumors relies on histological examination, we highlight the importance of their knowledge for the clinician, especially when in presence of patients with multiple lesions that may be the cutaneous marker of a cancer-prone syndrome. The dermatologist is therefore in a privileged position to recognize these lesions, which is extremely important to provide further propedeutic, appropriate referral and genetic counseling for these patients.

Three different clinical faces of the same histopathological entity: hair follicle nevus, trichofolliculoma and accessory tragus

AbstractBACKGROUND:Hair follicle nevus is a rare, congenital hamartoma with follicular differentiation characterized histologically by numerous, tiny, mature hair follicles. Trichofolliculoma, the histopathological features of which are quite similar to those of hair follicle nevus, is also a hamartoma that differs from hair follicle. Accessory tragus is a relatively common, benign congenital abnormality of the external ear with an incidence rate of 1 to 10 per 1,000 live births.OBJECTIVE:This study seeks to assess the discriminatory value of currently available, histological criteria in the differential diagnosis of hair follicle nevus, accessory tragi and trichofolliculoma.METHODS:Twenty-one patients comprising 9 cases of hair follicle nevus, 8 accessory tragi patients and 4 trichofolliculoma cases, were recruited to perform the study.RESULTS:There were 10 males and 11 females in the study group. No significant difference was observed between the three study groups in terms of age, gender or histopathological parameters such as density of hair follicles, subcutaneous fat score and presence of connective tissue framework. Cartilaginous component was seen in 8 cases that were diagnosed as accessory tragi, while central cyst and radiating hair follicles were seen in 4 cases which were diagnosed as trichofolliculoma.CONCLUSION:The results of our study showed that diagnostic discrimination of these diseases could be made only with the clinicopathologic correlation because of their clinical and histopathological similarities.

Carcinoma de la mama triple negativo aspectos morfológicos y expresión de CK 5/6 / Triple negative breast cancer morphological aspects and CK 5/6 expression

El carcinoma mamario es una enfermedad heterogénea, parámetros de clasificación, factores pronósticos, no siempre predicen su curso clínico. La genética molecular, los ha estratificado en grupos diferentes a la clasificación morfológica. Trabajos respaldan que un grupo específico: carcinoma de “tipo basal” tiene peor pronóstico, es frecuentemente triple negativo, es decir: RE(-), RP(-), C-erbB-2(-) expresa citoqueratinas de epitelios basales, como la citoqueratina 5/6 (CK5/6, planteamos determinar los aspectos morfológicos de estos carcinomas, identificar la frecuencia en la que expresan CK5/6 por inmunohistoquímica, relacionarlos con parámetros clínicos disponibles. Se seleccionaron 91 carcinomas entre 2003-2008 se les realizó CK5/6. 34 (37,4 por ciento) fueron TN-CK5/6(+) y 57 (62,6 por ciento) fueron TN-CK5/6(-). Las características morfológicas descritas se observaron en ambos grupos, más frecuentemente en los carcinomas TN-CK5/6(+). La detección de estos tumores por inmunohistoquímica es una forma práctica, rentable de identificar a este grupo de peor pronóstico en la práctica diaria.

Breast cancer is heterogeneous disease classification parameters prognostic factors are not always predictors its clinical course. Molecular genetics are categorizing in different ways, as the well-known morphologic classification. Studies endorse specific group within this classifying system: Basal-like carcinomas, has worst prognosis; tends to be triple-negative: ER(-), RP(-), Erb-B2(-); expresses basal cytokeratins, such as cytokeratin 5/6 (CK5/6). Considered determining morphological aspects, frequency in which they express CK5/6 through immunohistochemistry, and contrasting them to existing clinical parameters. 91 carcinomas were selected between the years 2003-2008 and checked for CK5/6. Or the aforementioned cases, 34 (37.4 percent) resulted TN-CK5/6(+) and 57(62.6 percent) resulted TN-CK5/6(-). Morphological aspects described for and carcinomas were observed in both groups, though they were more frequent in breast carcinomas TN-CK5/6(+). For this reason, detecting these tumors using immunohistochemistry is a practical, worthwhile, and convenient way to identify this group with the worst prognosis on our daily routines.

Trichoadenoma of Nikolowski.

Trichoadenoma of Nikolowski is a rare benign cutaneous tumor, which is usually solitary, nodular and occurs on the face or buttocks any time during adult life. The morphological differentiation of trichoadenoma is situated between a trichofolliculoma and a trichoepithelioma with hair follicle-like direction of differentiation. We report this case of trichoadenoma in a 28-year-old man who presented with a solitary nodular and ulcerated swelling in the gluteal region, gradually increasing in size. Excision biopsy revealed characteristic features consistent with trichoadenoma. We report this case in view of its rarity.