Panfolliculoma and histopathologic variants: a study of 19 cases

A case of retro-auricular panfolliculoma mimicking basal cell carcinoma: A rare adnexal tumor with a review of the literature

Key Clinical Message

A rare case of slow-growing retro-auricular panfolliculoma is presented. The lesion was biopsied to rule out basal cell carcinoma but histopathology revealed a follicular tumor with differentiation toward all segments of the hair follicle. Panfolliculoma is a benign follicular tumor with no report of recurrence after surgical excision and no malignant transformation of the previously reported cases.

Abstract

Panfolliculoma is a rare slow growing adnexal tumor, characterized by differentiation toward all parts of the hair follicle including the infundibulum, isthmus, stem, and bulbs. Clinically this adnexal tumor may mimick basal cell carcinoma and other adnexal neoplasm including trichoblastoma and trichoepithelioma. In this study, we present a rare case of slow-growing retro-auricular panfolliculoma of a 70-year-old female mimicking basal cell carcinoma that was successfully excised without recurrence.

Bulboma: A Benign Keratosis With Differentiation Toward the Lower Segment of the Hair Follicle

ABSTRACT

Bulboma is an appellation proposed to designate a distinctive solitary keratosis exhibiting differentiation toward the bulb of the lower segment of the hair follicle. Bulboma is composed of a papillated proliferation of epithelial cells beneath which is a broad front of interconnected follicular papillae. Overlying these coalescing follicular papillae are follicular germinative cells ascending into matrical cells and supramatrical cells. Cells demonstrating differentiation toward Huxley's and Henle's layer of the inner root sheath at the level of the bulb are present including strikingly bright eosinophilic trichohyalin granules and the blue-grey corneocytes of the stem. There is overlying hypergranulosis and orthokeratosis. The clinical and histopathological findings in 4 cases of bulboma, a rare, benign solitary keratosis are presented.

Panfolliculoma: Report of the Youngest Case and Literature Review of Its Histopathologic Variants

Background: Panfolliculoma (PF) is a relative rare, benign follicular tumor comprised of all elements of the hair follicle, with a limited number of cases reported in the literature. Articles on the demographic and pathological analysis of this tumor are also lacking. Case presentation: In this report, we presented an unusual case of cystic PF on the back of a 14-year-old male, and we performed a thorough literature review and analysis of all previously reported cases. Conclusions: PF is a rare benign follicular neoplasm with characteristic differentiation toward all components of the hair follicle. In our analysis, PF occurred most frequently on the head region and was usually diagnosed in middle- to old-aged persons, with cystic PF being the most common histologic subtype. Since this tumor is rare and easily misdiagnosed as other tumors both clinically and pathologically, a thorough understanding of the histopathological manifestations and differential diagnosis of this tumor is necessary for both dermatologists and pathologists.

Melanocytic Panfolliculoma: A Case Report of a Rare Benign Follicular Tumor

ABSTRACT

Panfolliculomas (PF) are rare, benign, follicular tumors that differentiate toward multiple components of the hair follicle, and several variants have been described. We present a case of a rare pigmented PF presenting on actinically damaged skin in an 83-year-old man, which was clinically concerning for malignancy. This tumor arose near an area of atypical squamous proliferation and has evidence of infundibular, outer root sheath, and matrical differentiation and foci of heavy melanin pigmentation and increased melanocytes. We propose the novel designation of "melanocytic PF," akin to melanocytic matricoma but with panfollicular differentiation.

Pilomatrical Acanthoma: An Extremely Rare Intraepidermal Variant of Pilomatricoma

ABSTRACT

Pilomatrical differentiation can be observed in a variety of benign and malignant tumors, with the most common prototype being pilomatricoma. Pilomatricoma often presents in the deep dermis or subcutis, and the sole involvement of epidermis is extremely rare. In our current case series, specimens from 5 patients were included with an average age of 68 years. All lesions presented as solitary verrucous or keratotic papules on the extremities, with 1 lesion having a prominent horn. All lesions have a variable mixture of basaloid matrical cells and shadow cells, and all lesions express β-catenin (strong nuclear and cytoplasmic), lymphoid enhancer-binding factor 1 within the matrical component, and pleckstrin homology-like domain family A member 1. The histomorphology and immunoprofile of all lesions are of pilomatrical differentiation, confined to the level of the epidermis. Based on these findings and analogous to the terminology used for other benign intraepidermal proliferations (hidroacanthoma simplex and epidermolytic acanthoma), we propose the term "pilomatrical acanthoma" for these rare lesions.

Panfolliculoma: A Clinical Case Report

Panfolliculoma is a benign neoplasm of follicular differentiation, and its morphological characteristics are similar to those of trichoblastoma, but it shows greater follicular differentiation. A 55-year-old female patient, visited for a dermatological consultation, presented comedo-like lesions on the eyelids, which were accompanied by moderate pruritus that spread gradually. On examination, the patient had localized dermatosis on the face, which symmetrically affected both upper eyelids and to a lesser extent the lower eyelids. The lesions consisted of papulonodular neoformations, comedones, and redundant skin, and a biopsy was performed. The histopathological report mainly described the presence of atrophic epidermis and dermis that was occupied entirely by a neoplasm of epithelial strain, comprising cystic structures that were surrounded by infundibular epithelium of an internal radicular sheath. Panfolliculoma is a rare benign neoplasm of follicular differentiation, and its morphological characteristics are similar to those of trichoblastoma, the pathologist must perform the clinicopathological correlation to establish the correct diagnosis.

Panfolliculoma with an endophytic architecture resembling a hair follicle: a report of three cases

Panfolliculoma is a benign follicular tumor comprised of all components of the hair follicle. We report three cases of panfolliculoma with a solid, endophytic architecture, which at scanning magnification had the profile of a hair follicle. The epithelial components included uniform dark blue germinative cells, matrical cells, clear cells and cells containing trichohyaline granules. All the cases also had a central hyperkeratotic horn resembling a hair shaft. Two patients were female and one was male. Two lesions were located on the head and neck, and one was located on the leg. Clinical differential diagnoses included basal cell carcinoma, foreign body and cyst.

A rare cutaneous adnexal neoplasm: cystic panfolliculoma

A cystic panfolliculoma is a benign follicular neoplasm which recapitulates several portions of the hair follicle. The patient was a 64-year-old Caucasian female who presented with a new growth on her right forearm. The lesion had slowly enlarged over the previous 11 months. She complained of it bleeding on several occasions and being very tender when touched. On exam was an 8 mm firm pink papule which appeared slightly eroded. The growth was excised in clinic. Histology showed a well-circumscribed neoplasm with foci of matrical, infundibular, inner and outer root sheath differentiation. A BerEp3 labeled focal areas of follicular germinative differentiation at the periphery of the proliferation. The lesion was narrowly excised in the available planes of section. The surgical site healed well and there are no residual symptoms from the tumor.