Panfolliculoma (PF) is a rare benign tumor with signs of differentiation toward all components of the hair follicle (HF). Cystic panfolliculoma (CPF) is a subset of PF with histological similarity to trichofolliculoma making the differential diagnosis difficult in some cases. Immunohistopathological investigations of PF have been reported; however, previous studies focused mostly on the expression profile of the outer root sheath markers. Read More
Some authors have reported that the secondary hair follicles in trichofolliculomas (TF) undergo regressive changes and are subsequently replaced by the developed sebaceous elements, and that folliculosebaceous cystic hamartoma (FSCH) is a TF at a very late stage. In the present study, we revaluated the histopathological features of 40 TF lesions, focusing on their chronological changes. The results of the present study indicate that while the secondary follicles in the TF exhibited the hair cycle, the normal hair cycle was out of control, and tertiary hair follicles randomly developed from the involuting secondary follicles. Read More
Trichoadenoma is a rare benign, slowly growing, cutaneous tumour of the hair follicle first described by Nikolowski in 1958. It presents as a non-specific nodule over the face or buttocks. However, unusual sites such as the neck, upper arm, thigh, shoulder, and shaft of the penis may also be affected. Read More
Folliculo-sebaceous hamartomas comprise a series of entities whose boundaries are imprecise. We present the clinical case of a folliculo-sebaceous cystic hamartoma of genital localization where the diagnosis was established based on the epithelial proliferation, but mostly, on the characteristic stroma. Because this lesion lacked of the cystic component, we mention the most frequent differential diagnoses and review the literature of the few cases published on this infrequent localization. Read More
A 6-year-old male presented with a protruding hair emerging from a temporally located nodule on his left upper eyelid 5mm above the eyelid margin since birth. The lesion was excised and sent to histopathology. The features were consistent with congenital sebaceous trichofolliculoma, a rare hamartomatous skin lesion. Read More
Hair follicle nevi are rare, benign, congenital hamartomas that usually occur in the distribution of the first brachial arch. Histopathologically, the distinction between hair follicle nevus, trichofolliculoma, and accessory tragus has recently come into question, and it may be that they are all on a spectrum of the same condition. We report the case of a 7-day-old boy who presented with a "tag"-like lesion on his midline chin that had been present since birth. Read More
We herein report a case of hair follicle nevus, a rare hamartoma found on the face and showing follicular differentiation, which was associated with sebaceous hyperplasia. Dermoscopy of the lesion showed yellow globules surrounded by crown vessels/telangiectasias and scattered tiny hairs. Histopathological investigation revealed hyperplasia of the sebaceous glands and proliferation of well-differentiated vellus hair follicles. Read More
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. Read More
A single intraperitoneal injection of 50 or 75 mg/kg N-methyl-N-nitrosourea in male Sprague-Dawley rats at 4 weeks of age, dose-dependently resulted in cutaneous epithelial cysts and tumors of pilosebaceous origin. Cysts were composed of epidermal cysts or mixed epidermal and inner root sheath hybrid cysts. The majority of induced tumors were keratoacanthomas. Read More
Initial investigations reported GATA3 to be a sensitive and relatively specific marker for mammary and urothelial carcinomas. Recently, GATA3 expression has been described in several other epithelial tumors. However, there has been only limited investigation of GATA3 expression in cutaneous epithelial tumors. Read More
Background: 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. Read More
Background: Trichofolliculoma is a rare benign tumor consisting of a pilosebaceous follicle hamartoma. While diagnosis of this condition is generally straightforward, fortuitous discovery of an atypical presentation can occur during histological examination of a biopsy or surgical sample.
Patients And Methods: We report herein on 8 patients aged between 8 and 75 years illustrating the wide spectrum of clinical presentation of this lesion, for which there are numerous differential diagnoses in the event of atypical clinical (lack of central whitish hair plug) or topical features (extra-facial site). Read More
Sebaceous trichofolliculoma is considered as hamartomatous lesion with follicular differentiation. In this study, we demonstrated a classic histopathologic picture of sebaceous trichofolliculoma in a 65-year-old male presented with large sized right cheek swelling. Read More
A 29-year-old Japanese man presented to our institution with a nodule on his nose that had increased in size since childhood. Physical examination indicated the presence of an elastic, firm, pedunculated red nodule measuring 15 mm in size. Dermatoscopic examination of the nodule indicated a yellowish-white network, yellowish-orange dots/globules at its center, and a pinkish-white structureless peripheral area. Read More
Trichofolliculoma represents abortive differentiation of pluripotent skin cells toward hair follicles. We present a case of an adult female with lobulated mass involving the tip and dorsum of the nose for the last 15 years. The systemic and radiological examinations were noncontributory. Read More
Understanding the epigenetic mechanisms that control the activation of adult stem cells holds the promise of tissue and organ regeneration. Hair follicle stem cells have emerged as a prime model to study stem cell activation. Wnt/β-catenin signaling controls multiple aspects of skin epithelial regeneration, with its excessive activity promoting the hyperactivation of hair follicle stem/progenitor cells and tumorigenesis. Read More
Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma characterized by follicular, sebaceous, and mesenchymal elements. Folliculosebaceous cystic hamartoma is probably not as rare as previously thought and its inclusion in the differential diagnosis of asymptomatic skin colored papules or nodules is warranted, especially if it is present in the head and neck region. Read More
Objective: Skin adnexal tumours (SAT) as a whole are rare tumours, and most of our current knowledge on SAT is from single case reports or small series focused on single histotypes. The purpose of this paper is to review a series of benign and malignant SAT diagnosed in a 20-year period.
Methods: All consecutive cases of SAT diagnosed between January 1992 and Dicember 2011 were retrieved. Read More
Various types of diseases can involve the nasal vestibule. Diagnosis and treatment of a nasal vestibular mass is often challenging due to the anatomical features of the nasal vestibule. Here, we present four cases with nasal vestibular masses. Read More
Trichofolliculoma is a pilosebaceous follicle hamartoma in which several hairs are formed within single pilosebaceous unit and protrude out of single orifice. Herein we report a 45-year-old woman with a trichofolliculoma of the eyebrow. Read More
Trichofolliculoma is a rare hair follicle hamartoma, which is often regarded as a hair follicle tumor. Mostly, it presents as a papule or nodule, involving the skin of the face and scalp area. A central, dilated keratin plugged ostium with vellus hair(s) is often present. Read More
Two unusual Carney complex patients are described. In one of them, several cutaneous biopsies revealed myxoid lesions that were rather more close to authentic adnexal neoplasms with myxoid stroma than to a "myxoma with an epithelial component." These included lesions resembling trichofolliculoma, infundibular cyst, and trichodiscoma. Read More
Background: Folliculosebaceous cystic hamartoma (FSCH) is a relatively recently described malformation with follicular and sebaceous components and a particular type of stroma with adipocytes. We conducted an anatomo-clinical study in order to clarify the clinical and histological characteristics of FSCH.
Materials And Methods: We included all cases of FSCH diagnosed between 1985 and February 2011 at our dermatopathology laboratory. Read More
Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma composed of dilated folliculosebaceous units and mesenchymal elements. It presents as a papule or nodule usually on the face and scalp, rarely on the genital or trunk area. Histologically, FSCH shares several similar features to sebaceous trichofolliculoma. Read More
Bone morphogenetic proteins (BMPs) play essential roles in the control of skin development, postnatal tissue remodelling and tumorigenesis. To explore whether some of the effects of BMP signalling are mediated by microRNAs, we performed genome-wide microRNA (miRNA) screening in primary mouse keratinocytes after BMP4 treatment. Microarray analysis revealed substantial BMP4-dependent changes in the expression of distinct miRNAs, including miR-21. Read More
Biologic samples from 18 (12 female, 6 male) Siberian hamsters (Phodopus sungorus) representing an aged colony (17 to 27 mo) were examined. Values for CBC and serum biochemical parameters were determined, and macroscopic and microscopic pathologic evaluations were performed. Blood urea nitrogen levels were significantly higher in male (54. Read More
Nevus lipomatosus superficialis (NLS) is an uncommon hamartomatous lesion of the skin characterized by the presence of clusters of mature fat cells among the collagen bundles of the dermis. Usually, the number of adnexal structures is reduced in NLS as compared to the normal adjacent skin, but their morphology is not altered. Nevertheless, in some instances, associated pilar abnormalities have been reported. Read More
Background: Although skin carcinogenesis has been widely investigated, only limited information is available for epidermal tumors, while even less is known about other skin structures. Alterations in the β-catenin pathway have been reported in several epidermal tumors, while little is known about in adnexal tumors. This study was performed to assess alterations in the β-catenin pathway associated with adnexal tumors, and to investigate the mechanisms underlying these alterations. Read More
Aims: Differential diagnosis between the group of trichoadenoma, trichofolliculoma, trichoepithelioma, trichoblastoma and basal cell carcinoma has been creating some difficulties for the pathologist and the clinicians, particularly in the presence of small specimens.
Material And Methods: A total of 30 cases of benign tumours of cutaneous appendages originating from the hair follicle and 30 cases of basal cell carcinoma were retrieved from the archives deposited from 2004 to 2008.
Results: The expression of CD10 in both tumours was graded from  to [2+] for each case. Read More
The histogenesis of folliculosebaceous cystic hamartoma (FSCH), including the origin of the frequently associated adipocytes and other mesenchymal components, remains unclear. There are controversial problems regarding FSCH, such as the relationship between FSCH and trichofolliculoma (TF), and the exact concept of sebaceous TF. Fourteen FSCHs and 1 sebaceous TF were revaluated for the histopathology and studied for immunohistochemical profile of various cytokeratins, hair follicular stem cell markers, and others. Read More
Few investigations on the histopathology of trichofolliculoma (TF) have so far included an immunohistochemical study. To seek new insight into TF with a revaluation of the histopathological features and an investigation of the immunohistochemical profile, 14 TFs were revaluated for the histopathology and the immunohistochemical profile of various cytokeratins (CKs), hair follicle stem cell markers, and others. The CK15 expression was upregulated in the basal cells from the primary cystic structures beyond to secondary follicles without expression of CK19. Read More
Bone morphogenetic proteins (BMPs) play pivotal roles in the regulation of skin development. To study the role of BMPs in skin tumorigenesis, BMP antagonist noggin was used to generate keratin 14-targeted transgenic mice. In contrast to wild-type mice, transgenic mice developed spontaneous hair follicle-derived tumors, which resemble human trichofolliculoma. Read More
Folliculosebaceous cystic hamartoma (FCH) is a relatively rare and recently described lesion of the skin. Mostly, it involves the skin of the head and neck area. It is considered by most authors as a form of non-neoplastic cutaneous hamartoma comprising follicular, sebaceous and stromal elements. Read More
Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units invested in mesenchymal elements. These solitary lesions typically affect adults, have a predilection for the central face or scalp, and remain less than 1.5 cm in greatest dimension. Read More
We report a case of a superficial angiomyxoma with a trichofolliculoma, found on the trunk of a 51-year-old man. The tumor, measuring 4 cm in maximum diameter and located in the reticular dermis and subcutaneous tissue, was composed of a conglomerate of multiple myxomatous nodules with mucinous stroma and stellate cells. Thin-walled blood vessels were prominent. Read More