Panfolliculoma with sebaceous differentiation--a case report

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.

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.

Basal Cell Carcinoma With Matrical Differentiation: Clinicopathologic, Immunohistochemical, and Molecular Biological Study of 22 Cases

Basal cell carcinoma (BCC) with matrical differentiation is a fairly rare neoplasm, with about 30 cases documented mainly as isolated case reports. We studied a series of this neoplasm, including cases with an atypical matrical component, a hitherto unreported feature. Lesions coded as BCC with matrical differentiation were reviewed; 22 cases were included. Immunohistochemical studies were performed using antibodies against BerEp4, β-catenin, and epithelial membrane antigen (EMA). Molecular genetic studies using Ion AmpliSeq Cancer Hotspot Panel v2 by massively parallel sequencing on Ion Torrent PGM were performed in 2 cases with an atypical matrical component (1 was previously subjected to microdissection to sample the matrical and BCC areas separately). There were 13 male and 9 female patients, ranging in age from 41 to 89 years. Microscopically, all lesions manifested at least 2 components, a BCC area (follicular germinative differentiation) and areas with matrical differentiation. A BCC component dominated in 14 cases, whereas a matrical component dominated in 4 cases. Matrical differentiation was recognized as matrical/supramatrical cells (n=21), shadow cells (n=21), bright red trichohyaline granules (n=18), and blue-gray corneocytes (n=18). In 2 cases, matrical areas manifested cytologic atypia, and a third case exhibited an infiltrative growth pattern, with the tumor metastasizing to a lymph node. BerEP4 labeled the follicular germinative cells, whereas it was markedly reduced or negative in matrical areas. The reverse pattern was seen with β-catenin. EMA was negative in BCC areas but stained a proportion of matrical/supramatrical cells. Genetic studies revealed mutations of the following genes: CTNNB1, KIT, CDKN2A, TP53, SMAD4, ERBB4, and PTCH1, with some differences between the matrical and BCC components. It is concluded that matrical differentiation in BCC in most cases occurs as multiple foci. Rare neoplasms manifest atypia in the matrical areas. Immunohistochemical analysis for BerEP4, EMA, and β-catenin can be helpful in limited biopsy specimens. From a molecular biological prospective, BCC and matrical components appear to share some of the gene mutations but have differences in others, but this observation must be validated in a large series.

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.

Panfolliculoma and histopathologic variants: a study of 19 cases

Panfolliculoma (PF) is an uncommon benign follicular neoplasm exhibiting differentiation toward all components of a hair follicle. Several pathologic manifestations have been described in a limited number of cases. We studied 19 cases of PF to summarize the clinical parameters and to classify this unique neoplasm histopathologically. A study of the largest sample series of PF has been performed here. The lesions affect both genders after age 20. The head is the most common site of PF of all types. On microscopic examination, all cases demonstrated advanced follicular differentiation by showing cell components of infundibulum, isthmus, stem, bulb, and mesenchymal papilla. Based on the findings and various patterns in histopathology, we classified PF into 3 subtypes: nodular, superficial, and cystic. The superficial and cystic variants account for most of the cases in our study. The histopathologic differential diagnosis is also discussed for each subtype.