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

Abstract

BACKGROUNDHair 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.OBJECTIVEThis study seeks to assess the discriminatory value of currently available, histological criteria in the differential diagnosis of hair follicle nevus, accessory tragi and trichofolliculoma.METHODSTwenty-one patients comprising 9 cases of hair follicle nevus, 8 accessory tragi patients and 4 trichofolliculoma cases, were recruited to perform the study.RESULTSThere 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.CONCLUSIONThe 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.

Hair Follicle Nevus Located on the Neck: Comparison with Accessory Tragus, Cervical Chondrocutaneous Branchial Remnants and Trichofolliculoma

“…In contrast, other authors still consider HFN as a separate entity from trichofolliculoma, and they suggest that it is necessary to exam multiple serial sections in order to exclude the presence of central cystic structures 8 . Recently, Karabulut et al 2 compared HFN, accessory tragus, and trichofolliculoma from a histopathologic aspect. There was no significant difference among the three diseases in the density of hair follicles, subcutaneous fat score, and presence of connective tissue framework 2 .…”

“…Recently, Karabulut et al 2 compared HFN, accessory tragus, and trichofolliculoma from a histopathologic aspect. There was no significant difference among the three diseases in the density of hair follicles, subcutaneous fat score, and presence of connective tissue framework 2 . In the present study, we performed a pilot immunohistochemical study with CK19.…”

“…Hair follicle nevus (HFN) is a rare, benign, follicular hamartoma that usually presents as a congenital, asymptomatic nodule on the face. Differential diagnoses of HFN include accessory tragus, cervical chondrocutaneous branchial remnants (CCBR) and trichofolliculoma, but recently there has been a debate regarding whether they are on a spectrum of the same entity 1 2 3 4 . Here we report the case of a HFN which presented as a solitary papule on the neck.…”

Umbilicated Hairy Auricular Mass Mimicking Accessory Tragus

“…Histologically, hair follicle nevus and accessory tragi are the most difficult to distinguish of the lesions in the differential diagnosis of TFs. Their histologic backgrounds are very similar except the amounts of hair follicles and subcutaneous fat [12]. TF is a pilar tumor and intermediate in differentiation between a trichoepithelioma, which misses maturation of the hair follicle and a hair follicle nevus, which is simple hyperplasia of the hair follicle.…”

Trichofolliculoma of the nasal vestibule

“…Однако, по данным исследования Y. Karabulut и соавт., из 21 пациента у 8 в препаратах преаурикулярного отростка определяются хряще вые компоненты, у 4 больных центральная киста и волосяные фолликулы были расценены как трихо фоллликулома, у 9 обследованных был диагности рован волосяной невус [7].…”