Folliculosebaceous Units Research Articles

Poroid Neoplasms: A Clinicopathological Study of 13 Cases.

Poroid neoplasms (PN) are a heterogeneous group of tumors deriving from sweat glands and folliculo-sebaceous units. Their histological classification and clinical features are challenging. Our aim was to report clinicopathological features of poroid neoplasms. It is a retrospective study including all cases of poroid neoplasms registered at our Pathology laboratory of Niamey National Hospital (February 2020-February 2024). We registered 13 cases of benign poroid neoplasms: 10 classic poromas (CP) (76.9%), 2 poroid hidradenomas (PH) (15.4%) and 1 dermal duct tumor (DDT) (7.7%). Nine cases (69.2%) had preoperative clinical diagnosis of malignancy. The mean age was 41.1 years (range of 12-70 years) with a slight female predominance. Only 4/13 cases (30.8%) had classical palmoplantar locations. The tumors mean size was 3.7 cm (range of 0.4-8 cm). Clear cells were present in 7 cases (53.8%), apocrine ductal differentiation (mixed or pure) in 6 cases (46.2%), keratin horns in 2 cases (15.4%), squamous eddies in 6 cases (46.2%), melanin pigments in 1 case (7.7%) and sebaceous differentiation in 2 cases (15.4%). Unlike what is classically reported, our study shows that apocrine ductal differentiation, younger age and non-palmoplantar locations are common in poroid neoplasms.

Folliculosebaceous Cystic Hamartoma Arising in Miescher-Type Melanocytic Nevi.

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units associated with mesenchymal elements. Ansai et al reported that distinctive features of Miescher-type melanocytic nevi (MMCNs) accompanied 4.6% of FSCH; however, there have been no data about how often FSCH features accompany MMCNs. In this study, we used 7829 cases that had been histopathologically diagnosed as MMCNs of the face, neck, and scalp at the Department of Dermatopathology, Nippon Medical School Musashi Kosugi Hospital and observed whether features of FSCH accompanied them. Of the resected MMCNs, 274 of 7829 (3%) were accompanied by features of FSCH. The nose was the most common resection site, followed by the eyebrow area, ear, and cheek. The coexistence rate for the nevi on the nose and features of FSCH was as high as 10%-20%, and its rate increased with age. We found that FSCH appears mostly in seborrheic areas, such as the nose and cheek, which are rich in normal sebaceous glands. This suggests that nevi, especially on and around the nose, may induce FSCH or similar lesions.

Folliculosebaceous units are a frequent finding in early lichen sclerosus of the foreskin.

Folliculosebaceous units (FSU) has been considered an early target of inflammation in vulvar lichen sclerosus (VLS). This diagnostic clue is not reported in lichen sclerosus (LS) of the foreskin (FLS) that is normally hairless. We evaluated the presence and inflammation of FSU and sebaceous glands (SG) in LS of the foreskin. Histological specimens from therapeutic circumcision were assessed in order to evaluate the frequency and inflammation of FSU and SG in LS. Ninety-eight cases, grouped into 46 early (group 1) and 52 overt (group 2) FLS were included in the study. SG-FSU were found in 95.7% of group 1, and 65.4% of group 2 cases. Their density was inversely correlated with patient age (P=0.0014). We observed perifollicular inflammation in all cases with visible SG-FSU and frequent FSU abnormalities. SG and FSU were frequent in early FLS and decreased in advanced disease and adults. We hypothesize that SG and FSU are involved in the inflammatory process leading to FLS. These data, which need further investigation, could help to better understand the pathogenesis of FLS.

Specificity of granular IgM deposition in folliculosebaceous units and sweat gland apparatus in direct immunofluorescence (DIF) of lupus erythematosus

Diagnosis of lupus erythematosus (LE) in direct immunofluorescence testing is based on the finding of positive immunofluorescence at the dermoepidermal junction (DEJ). We sought to evaluate the sensitivity of IgM deposition at the DEJ and adnexal structures in the diagnosis of lupus erythematosus. We conducted a retrospective study of 100 previously diagnosed cases of lupus erythematosus and 158 cases of other immune-mediated dermatosis. Deposition of IgG, IgM, IgA, and C3 at the DEJ, follicular units, and sweat glands were recorded. Presence or absence of adnexal structures was documented. The immunoreactant deposition was documented as linear, coarse granular, or stippled. The most frequently deposited immunoreactant in lupus erythematosus cases was IgM along the DEJ and stromal-epithelial junction of hair follicles and sweat glands. IgM deposition along the stromal-epithelial junction of hair follicles and sweat glands was strongly associated with a diagnosis of lupus erythematosus compared with other immune-mediated diseases collectively (P value<.001). The pattern of IgM in lupus and dermatomyositis is granular, in contrast to the linear deposition in the other disorders evaluated. This was a retrospective study of archived material. Granular IgM deposition at the stromal-epithelial junction of cutaneous adnexal structuressuggests a diagnosis of lupus erythematosus or dermatomyositis.

Ectopic folliculosebaceous units at the coronal sulcus

Tyson glands were described in the 17th century as modified sebaceous glands of the coronal sulcus of the penis. However, this description and other early texts supporting the existence of Tyson glands were not accompanied by illustrations. The existence of such glands has been passing through the literature without adequate graphical demonstration, which has contributed to controversial debates. Herein we present a case of a partial penectomy performed on a 65-year-old man with a squamous cell carcinoma of the penis. In this case we identified sebaceous glands as well as folliculosebaceous units in the coronal sulcus. We also comparatively examined 12 cases of partial penectomy to search for sebaceous glands or folliculosebaceous units in the coronal sulcus or the preputium. We found neither sebaceous glands nor folliculosebaceous units at the coronal sulcus or the mucosal aspect of the prepuce. We conclude that: (1) folliculosebaceous units are possible in the coronal sulcus, as the current case illustrates for the first time in literature and (2) the current case is an oddity, probably induced by the accompanying squamous cell carcinoma, and therefore it may represent an ectopic folliculosebaceous unit rather than an anatomic variation.

Vulvar Adnexal Lesions: A 32-Year, Single-Institution Review From Massachusetts General Hospital

Because the skin and modified mucosal surfaces of the vulvar region contain dense apocrine glands and anogenital mammary-like glands, in addition to eccrine glands and folliculosebaceous units, benign as well as malignant lesions derived from these adnexal structures are, not surprisingly, found in the vulva. However, their incidence occurring in the vulva has not been reported, to our knowledge. To determine the incidence of various vulvar adnexal lesions. We performed a retrospective review (1978-2010) of the cases at our institution. A total of 189 vulvar adnexal lesions were identified. Most of these lesions were benign (133 of 189; 70%), with hidradenoma papilliferum being the most common, followed by syringoma and various types of cysts. Rare cases of tubular adenoma, poroma, spiradenoma, hidradenoma, cylindroma, sebaceoma, and trichoepithelioma were identified. Malignant adnexal neoplasms comprised the remaining 30% (56 of 189) of the cases. Extramammary Paget disease was the most common (49 of 56), and 29% (14 of 49) demonstrated an invasive component. Rare cases of basal cell carcinoma, sebaceous carcinoma, apocrine carcinoma, adenoid cystic carcinoma, and spiradenocarcinoma were identified. In this retrospective review, we identified several benign entities that have not been previously reported on the vulva, namely pilomatricoma, poroma, spiradenoma, and sebaceoma. Hidradenoma papilliferum and extramammary Paget disease were the most common benign and malignant adnexal neoplasms, respectively. The spectrum of various vulvar adnexal lesions appears to reflect the frequency of the underlying glandular elements.

Expanding the histologic findings in smallpox‐related post‐vaccinial non‐viral folliculitis

Post-vaccinial non-viral folliculitis has been recognized in the past decade as a new adverse cutaneous reaction to smallpox vaccination. Contrary to more serious smallpox vaccine reactions, post-vaccinial non-viral folliculitis has a benign course and resolves spontaneously within approximately 7 days. We describe additional histopathologic findings associated with post-vaccinial non-viral folliculitis, which has only been described once previously. New findings include the presence of a neutrophilic or lymphohistiocytic infiltrate that is concentrated around the hair follicles. We compare our findings to the follicular nature of varicella and herpes zoster infections, generating the hypothesis of deposition of vaccinia protein within folliculosebaceous units as a potential pathophysiologic mechanism behind post-vaccinial non-viral folliculitis.

Diagnostic utility of direct immunofluorescence findings around hair follicles and sweat glands in immunobullous disease

Inherent to some immunobullous disorders is potential for intraepidermal or dermal-epidermal junction fragility, a phenomenon that may compromise biopsy specimen integrity and direct immunofluorescence (DIF) interpretation. In these situations, cutaneous adnexal structures (e.g. hair follicles, sweat apparatus) usually remain intact. Whether periadnexal DIF findings are reliable in diagnosing immunobullous conditions is unknown. We evaluated 56 cutaneous specimens with diagnostic immunoglobulin (Ig) deposition patterns that contained adnexal structures. In a corollary study, we examined 145 hematoxylin-eosin-stained frozen specimens to determine biopsy factors associated with the presence of adnexal structures. Periadnexal DIF findings offered diagnostic sensitivity in conditions with linear or cell-surface Ig deposition or lupus band. Periadnexal DIF findings were unreliable in dermatitis herpetiformis. Biopsy specimens from scalp and genitalia were most likely to contain folliculosebaceous units and sweat duct apparatus, respectively. Relative depth of biopsy correlated directly with the likelihood of identifying sweat duct apparatus but not folliculosebaceous units. Periadnexal DIF findings may add diagnostic sensitivity in DIF evaluation of pemphigoid, pemphigus and lupus erythematosus. Pathologists can guide clinicians to biopsy certain anatomic sites and to obtain sufficient biopsy depth to increase the probability of capturing adnexal structures and, therefore, diagnostic yield from DIF specimens.

Central centrifugal cicatricial alopecia: possible familial aetiology in two African families from South Africa

Central centrifugal cicatricial alopecia: possible familial aetiology in two African families from South Africa

Advances in folliculosebaceous cystic hamartoma

Clinically, folliculosebaceous cystic hamartoma (FSCH)is uncommon and lacks distinct features. It often manifests as asymptomatic, skin-colored papules or nodules mostly distributed on the face. Histopathologically, it is a kind of hamartoma of skin appendages mainly characterized by the hyperplasia of folliculosebaceous units and mesenchymal tissues. The differential diagnosis mainly includes sebaceous trichofolliculoma and dermoid cyst. Its immunohistochemical manifestations are unspecific and associated with epithelial and non-epithelial component within the hamartoma. This paper presents an update on the knowledge about clinical and immunohistochemical manifestation of, diagnostic criteria and treatment for FSCH. Key words: Hamartoma; Epidermal cyst; Hair follicle; Sebaceous glands

Folliculosebaceous Cystic Hamartoma in a Patient with Neurofibromatosis Type I

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. We report one case of FSCH misdiagnosed as a neurofibroma. He was a 38-year-old man with a neurofibromatosis type I and a nodule on his left earlobe was excised under the impression of neurofibroma. Pathological examination revealed FSCH. Although FSCH is clinically not distinctive, awareness of the lesion is important to differentiate papulonodular or cyst-like cutaneous lesions.

Herpes folliculosebaceous ulcer in a patient with chronic lymphocytic leukaemia: an ulcerative variant of herpes folliculitis associated with herpesvirus invasion of folliculosebaceous units in immunocompromised hosts

Herpes folliculosebaceous ulcer in a patient with chronic lymphocytic leukaemia: an ulcerative variant of herpes folliculitis associated with herpesvirus invasion of folliculosebaceous units in immunocompromised hosts

Giant, Congenital Folliculosebaceous Cystic Hamartoma: A Case Against a Pathogenetic Relationship With Trichofolliculoma

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. Although giant FSCH variants have been documented, the congenital presentation of a giant FSCH stands in contrast to earlier views of its histogenetic relationship with trichofolliculoma. We describe a giant pedunculated FSCH arising from the posterior neck of a 9-month-old Hispanic male and discuss various aspects of this highly unusual case.

Dermoscopy of Trichostasis Spinulosa

T RICHOSTASIS SPINULOSA (TS) IS A RELAtively common but underdiagnosed disorder of hair follicles that retain successive telogen hairs. It has been described within skin lesions (secondary TS) or as an isolated finding (primary TS). Dermoscopy may help identify the characteristic hair tuft. We report 2 cases of TS. The first case involved a 23-year-old woman who presented with a long-standing history of a light-brown papule on the lower part of her back. There was a black punctum in the upper central area of the lesion (Figure 1). Dermoscopy showed a sparse pigment network, multiple commalike blood vessels that are typical of intradermal melanocytic nevi, a few peripheral vellous hairs, and a small hair tuft emerging from the central punctum (Figure 2). Histologic examination confirmed the presence of an intradermal melanocytic nevus along with dilated folliculosebaceous units containing several cross-sectioned hair shafts (Figure 3). The second case involved a 30-yearold man who presented with a micropapular eruption on both flanks. Dermoscopy showed multiple vellous hairs erupting through the follicles (Figure 4). Hair tufts are the result of folliculosebaceous hamartomas with multiple units around a central pore (trichofolliculomas) or retained hair shafts within follicles with infundibular keratosis (TS). Trichostasis spinulosa may appear as an isolated finding or in association with expansile nondestructive lesions that narrow hair infundibulae, such as melanocytic nevi, seborrheic keratoses, syringomas, or nodular basal cell carcinomas. Dermoscopy is helpful in diagnosing TS.

Dermatofibroma on the Palmar Surface of the Hand

Case 1: A 58-year-old man presented with a solitary asymptomatic nodule on his thumb (Figure A). After trauma with a rusty nail approximately 20 years ago, he had developed a small papule, which had enlarged gradually for a few days initially before stabilizing. His personal and family medical histories were unremarkable. Dermatologic examination revealed a 1-cm crater-like nodule on the left palmar area. This was a firm and nontender lesion that was fixed to the overlying skin but moved freely from underlying structures. There were no similar lesions elsewhere on his body. Case 2: A 52-year-old man presented with a nodular lesion on the left palmar surface of his thumb. The 0.8-cm lesion was lightly colored, with a central cup-shaped epidermal depression and thin epidermis. The patient described an insect bite to the area 15 years earlier as the precipitating event. The firm and nontender lesion was fixed to the overlying skin but moved freely from underlying structures (Figure B). Case 3: A 36-year-old man consulted for a nodular lesion, located on his left palmar surface, that had not enlarged or changed since appearing 3 years ago. He described mechanical trauma to the area as precipitating the lesion. Clinical examination revealed a 0.6-cm, well-circumscribed nodule, with a dome shape and colored skin. Clinically, the nodular lesion appeared to be a benign tumor (Figure C). In each case, the nodule was excised totally and histopathologic examination revealed a well-circumscribed, nonencapsulated nodule within the mid-dermis. Thick, acellular collagen bundles were arranged randomly in short fascicles through the center of the lesion. Cellular areas consisting of histiocytes and fibroblasts with a storiform pattern at the periphery of lesion were observed, but nuclear atypia and mitotic activity were not. Results of immunohistochemical stain with CD34 were negative, but in all cases were strongly positive for Factor XIIIa. Slight epidermal hyperplasia was present with orthokeratotic hyperkeratosis and flattened rete ridges in the overlying epidermis (Figure A-1, Figure B-1, Figure C-1). The subcutaneous fat and adjacent skin were normal. No folliculosebaceous units at the periphery of the lesion were seen, but a few eccrine sweet glands were noted. No recurrence appeared in 18 months of follow-up.

Two cases of folliculosebaceous cystic hamartoma.

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma composed of dilated folliculosebaceous units associated with mesenchymal elements. Two cases of FSCH with typical histopathological features are reported. Patient 1 was a 60-year-old man presented with a normal skin-coloured asymptomatic nodule on his scalp. Patient 2 was a 70-year-old man with an asymptomatic nodule on his right auricle that had persisted for the previous 15 years. In all, 34 cases of FSCH have been reported in the English literature. Clinically, the lesions are asymptomatic, usually rubbery to firm in consistency, and usually occur on or above the neck (> 90%). Most lesions do not exceed 25 mm in diameter (> 90%). Histopathologically, FSCH shares several similar features to sebaceous trichofolliculoma, but it is usually possible to differentiate these two tumours.

Exclusive Involvement of Folliculosebaceous Units by Herpes

The histopathological changes of herpes simplex, herpes zoster, and varicella are considered to be indistinguishable from one another. Evaluation of the clinical setting, with adjunctive studies if necessary, generally clarifies the specific diagnosis. Vesicular lesions in all three conditions can involve epidermal and adnexal epithelium with characteristic cytopathic features. We describe three patients with non-vesicular eruptions on the head and neck whose biopsies revealed exclusive folliculosebaceous involvement by herpes. All three patients developed typical herpes zoster within days of the biopsy. There is compelling scientific evidence in the literature indicating that, in herpes zoster, the virus is transported from dorsal root or trigeminal ganglia via myelinated nerves to the skin. These terminate at the isthmus of hair follicles and primary infection of follicular and sebaceous epithelium occurs. Spread of infection to the epidermis follows. In contrast, data pertaining to recurrent herpes simplex indicates that axonal transport of the virus from sensory ganglia to the skin is directed primarily to the epidermis, via terminal non-myelinated nerve twigs. The clinical evolution of our three cases and scientific data in the literature indicate that exclusive folliculosebaceous involvement by herpes, in the setting of a non-vesicular eruption, represents early herpes zoster.

Herpetic Cytopathic Features Confined to Folliculosebaceous Units: What does it Mean?

The histopathological changes of herpes simplex, zoster and varicella are considered to be indistinguishable from one another. The clinical setting with adjunctive studies generally clarifies the diagnosis. Vesicular lesions in all 3 conditions can involve epidermal and adnexal epithelium with characteristic cytopathic features. We describe 3 patients with non‐vesicular eruptions on the head and neck whose biopsies revealed exclusive folliculosebaceous involvement by herpes. All three patients developed typical herpes zoster within days of the biopsy. There is compelling scientific evidence in the literature indicating that, in herpes zoster, the virus is transported from dorsal root or trigeminal ganglia via myelinated nerves to the skin. These terminate at the isthmus of hair follicles and primary infection of follicular and sebaceous epithelium occurs. Secondary spread of infection to the epidermis follows. In contrast, data pertaining to recurrent herpes simplex indicates that axonal transport of the virus from sensory ganglia to the skin is directed primarily to the epidermis, via terminal non‐myelinated nerve twigs. The clinical evolution of our 3 cases and scientific data in the literature indicate that exclusive folliculosebaceous involvement by herpes, in the setting of a non‐vesicular eruption, represents early herpes zoster.

Giant folliculosebaceous cystic hamartoma of the upper extremity

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units invested in mesenchymal elements. These lesions have a striking predilection for the central face and scalp of adults. The vast majority of lesions present as 0.5-1.5-cm papules or exophytic nodules. A single case of giant FSCH has been reported on the upper back. A 32-year-old woman presented with a (15 cm in greatest dimension) plaque-like, multinodular lesion on her left upper arm for several years. The lesion was clinically suspected to be a nevus sebaceus. The skin excision showed numerous dermal and subcutaneous dilated follicular structures with peripherally radiating sebaceous lobules, hair follicles, and surrounding mesenchymal elements consistent with FSCH. To our knowledge, this is the second case of giant FSCH. Our case is unique for its larger size, more plaque-like growth, and location on an extremity when compared to the seminal case of giant FSCH.

Eccrine gland infiltration by mycosis fungoides.

After identifying prominent eccrine infiltration by atypical lymphocytes in a biopsy of tumor stage mycosis fungoides (MF), we sought to determine the pattern of eccrine epithelial infiltration in MF. The frequency, intensity, and distribution of infiltration of eccrine gland structures, including acrosyringium, duct and coil epithelium, was studied by examining 71 biopsy specimens from 42 patients with MF in which eccrine structures were present. These were obtained from a retrospective review of pathologic specimens from Duke University Medical Center from 1992 and 1993. At least focal eccrine infiltration was noted in 23 of the 71 biopsy specimens (32%). Immunohistochemical confirmation of T-lymphocyte phenotype was performed in the 23 cases with positive reaction to antibodies CD3 and CD45RO and negative reaction with CD20. Folliculosebaceous units were present in 22 of the 71 biopsy specimens and were at least focally involved by MF in 11 (50%) in this series. A control group of biopsy specimens of reactive dermatoses were characterized by more superficial location of lymphocytes, with more spongiosis and epithelial degenerative changes. These findings further illustrate the epitheliotropic behavior of MF.