Benign follicular tumors

A Proliferating Trichilemmal Tumor at an Uncommon Site Treated With Radical Excision: A Case Report and Literature Review

A proliferating trichilemmal tumor (PTT) is a rare, benign, exophytic tumor originating from the isthmus region of the outer root sheath of the hair follicle. Clinically, PTTs manifest as isolated, exophytic, firm nodules that have the potential to ulcerate. These tumors may occasionally originate from a pre-existing trichilemmal cyst, or they can emerge spontaneously. Most exclusively these lesions are seen on the scalp. However, rarely these tumors can be found in other anatomical areas. Our patient had a protruding mass in her shoulder for 20 years, and this is a rare site for the occurrence of these lesions; it could be the first case to document such a site, as far as we found in the literature. The mainstay treatment of the PTT is surgical excision of the tumor, assessing the histological margins to ensure sufficient resection was made, close monitoring, and follow-up with the patient.

Invasive Carcinoma With Skin Adnexal Trichilemmal Hair Follicular Differentiation Occurring in the Breast: A Case Report With Detailed Immunohistochemical and Molecular Analysis

Cutaneous-type adnexal tumors involving the breast are rare and create a diagnostic dilemma as they are often indistinguishable from primary mammary neoplasms. Tumors showing hair follicular differentiation are particularly challenging due to their rarity and the subtle appreciation of the intricate microanatomy of the hair follicle. We report a triple negative cutaneous-type adnexal carcinoma with follicular differentiation involving the breast to bring attention to the existence of these specialized group of tumors which should be managed differently from conventional triple negative carcinomas of the breast.

Urticarial vasculitis and systemic symptoms as initial presentation of Birt-Hogg-Dubé syndrome: A case report

Birt-Hogg-Dubé syndrome, an extremely rare genetic disorder, is characterized by the development of fibrofolliculomas, lung cysts and subsequent recurrent pneumothorax, and kidney neoplasia. This report highlights the case of a 56-year-old female with a history of right vestibular schwannoma status post stereotactic radiotherapy and vulva bartholin's gland carcinoma who was initially evaluated by primary care for a 6-month history of intermittent, red, raised, widespread rash accompanied by fever, chills, and body aches. A punch biopsy of the rash was performed, which was notable for an urticarial tissue reaction with focal changes of leukocytoclasia and negative direct immunofluorescence. Laboratory tests, which included an autoimmune genetic and periodic fever panel, were unremarkable. Whole genome sequencing returned positive for a pathogenic variant in folliculin gene, consistent with a diagnosis of Birt-Hogg-Dubé syndrome.

[A case of trichoblastoma of the auricular cavity and review of the literature]

Trichoblastoma（TB） is a rare germ cell skin adnexal tumor of the hair, and it is a rare follicular tumor of the skin that differentiates from the hair germ epithelium and is often regarded as a benign skin tumorHowever, it is poorly confined and has a local infiltrative growth pattern. tb occurs in the head and neck region, especially in the face, and presents clinically as a slow growing, well-defined and elevated nodule. TB is routinely treated surgically. Due to the lack of universally accepted treatment guidelines or protocols, the recurrence rate after surgery is high, which makes clinical cure more difficult. In this study, a 65-year-old female patient was found to have a swelling with recurrent rupture and pus flow from the right external auditory canal opening and the auricular cavity. After initial misdiagnosis as otitis externa, she was treated with conventional anti-infective therapy, but her symptoms did not resolve and gradually worsened before coming to our hospital. The condition presented in this case is relativelyrare,therepre,timely and accurate diagnosis and treatment are crucial for prognosis improvement of such diseases.

Tumor of follicular infundibulum - reappraisal in a series of 28 patients with critical review of the literature

BACKGROUND AND OBJECTIVES

Tumor of follicular infundibulum (TFI) has been described as a neoplasm - isolated and multiple - and in association with other lesions. Its histopathologic definition is controversial.

PATIENTS AND METHODS

We present a histopathologically analyzed series of 28 patients with TFI features. This has been supplemented by a search in MEDLINE on the literature on this subject. The corresponding figures given in these articles have been discussed and analyzed.

RESULTS

Patients comprised 16 women and twelve men. TFI features were seen in five patients with nevus sebaceous, two trichofolliculomas, one dilated pore Winer, eight viral warts, one dermatofibroma, six seborrheic keratoses, three actinic keratoses, one invasive squamous cell carcinoma, and one basal cell carcinoma in association with a squamous cell carcinoma/actinic keratosis. After study of the literature especially of solitary cases of TFI, we interpret such cases mostly as variants of seborrheic keratoses with variable degree of infundibular, isthmic and/or sebaceous differentiation with or without regression.

CONCLUSIONS

We regard TFI as an epithelial growth pattern which may occur in hamartomatous, inflammatory, infectious, reactive, or neoplastic conditions, in most solitary forms likely best classified within the histopathological spectrum of seborrheic keratoses.

Tumor des follikulären Infundibulums - Neubewertung in einer Serie von 28 Patienten mit kritischer Analyse der Literatur: Tumor of follicular infundibulum - reappraisal in a series of 28 patients with critical review of the literature

Hintergrund und Ziele

Der Tumor des follikulären Infundibulums (TFI) wurde als Neoplasie – isoliert und multipel – und in Assoziation mit anderen epithelialen Läsionen beschrieben. Seine endgültige histopathologische Definition wird kontrovers diskutiert.

Patienten und Methodik

Wir präsentieren eine retrospektive Serie von 28 Patienten mit TFI beziehungsweise TFI‐ähnlichen Veränderungen. Ergänzend wurde die in MEDLINE aufgeführte Literatur zum Thema TFI recherchiert und die darin publizierten Abbildungen interaktiv diskutiert und analysiert.

Ergebnisse

Unsere Patienten waren 16 Frauen und 12 Männer. TFI‐ähnliche Veränderungen fanden sich bei fünf Patienten mit Nävus sebaceus, zwei Trichofollikulomen, einer erweiterten Pore Winer, acht Virusakanthomen, einem Dermatofibrom, sechs seborrhoischen Keratosen, drei aktinischen Keratosen, einem invasiven Plattenepithelkarzinom und einem Basalzellkarzinom in Kombination mit Plattenepithelkarzinom/aktinischer Keratose. Nach Sichtung der Literatur, insbesondere von solitären Fällen von TFI, betrachten wir diese größtenteils als Variante von seborrhoischen Keratosen mit variablem Ausmaß von infundibulärer, isthmischer und/oder sebazärer Differenzierung mit oder ohne Regression.

Schlussfolgerungen

Wir werten TFI insgesamt als ein epitheliales Wachstumsmuster, das bei hamartomatösen, entzündlichen inkludierend infektiösen, reaktiven oder neoplastischen Prozessen auftreten und in den meisten solitären Formen am ehesten innerhalb des histologischen Spektrums seborrhoischer Keratosen eingeordnet werden kann.

Status of research on the development and regeneration of hair follicles

Hair loss, or alopecia, is a prevalent condition in modern society that imposes substantial mental and psychological burden on individuals. The types of hair loss, include androgenetic alopecia, alopecia areata, and telogen effluvium; of them, androgenetic alopecia is the most common condition. Traditional treatment modalities mainly involve medical options, such as minoxidil, finasteride and surgical interventions, such as hair transplantation. However, these treatments still have many limitations. Therefore, exploring the pathogenesis of hair loss, specifically focusing on the development and regeneration of hair follicles (HFs), and developing new strategies for promoting hair regrowth are essential. Some emerging therapies for hair loss have gained prominence; these therapies include low-level laser therapy, micro needling, fractional radio frequency, platelet-rich plasma, and stem cell therapy. The aforementioned therapeutic strategies appear promising for hair loss management. In this review, we investigated the mechanisms underlying HF development and regeneration. For this, we studied the structure, development, cycle, and cellular function of HFs. In addition, we analyzed the symptoms, types, and causes of hair loss as well as its current conventional treatments. Our study provides an overview of the most effective regenerative medicine-based therapies for hair loss.

Benign proliferating pilar tumor excised with Slow Mohs surgery: A case report

Proliferating pilar tumors are rare, benign, exophytic neoplasms, which can closely resemble a squamous cell carcinoma. We describe a patient with a large benign exophytic tumor on the scalp that had been slowly growing over 10 years. While this class of benign follicular tumors is rare, the standard of care is typically excision with clear histologic margins. In this case, this large scalp tumor was surgically excised with clear margins/permanent section margin control using "Slow Mohs" technique, with subsequent repair using a skin substitute dressing, followed by a delayed skin graft.

Trichoblastomas derived from the facial skin with tactile hair in aged house musk shrews (Suncus murinus)

BACKGROUND

Benign hair follicle tumors are relatively rare cutaneous neoplasms arising from hair follicle differentiation. These tumors are slow-growing solitary papules or nodules in the head, face or neck. The aim of this study was to describe 2 cases of trichoblastomas in tactile hair skin incidentally encountered in aged house musk shrews (Suncus murinus). In addition, this case report clarifies whether the characteristics in the tactile hair skin of Suncus murinus are different from those in humans and other animals.

CASE PRESENTATION

The animals were investigated the characteristics of the clinical findings, hematological and serum biochemical profiles (particularly, serum amyloid A levels (vSAA)), and histopathological results. Suncus murinus with the facial tumor showed weight loss and coarse fur. Hematological examinations indicated microcytic and normochromic anemia. Although few apparent changes were serum biochemically found in Suncus murinus, vSAA levels moderately increased and revealed inflammatory reactions. These lesions histopathologically showed the basaloid islands comprising peripheral palisading and dilated microcysts containing variable admixtures of free-floating cells such as neoplasm cells, giant cells, clear cells, mononuclear cells and erythrocytes.

CONCLUSIONS

The author concluded that trichoblastomas in Suncus murinus revealed growth and morphological characteristics that recapitulate part of embryological development in the tactile hair follicles. In the histological structure, their trichoblastomas in the tactile hair skin were different from those found in humans and animals such as cats, dogs and other wildlife.

Cellular Heterogeneity and Plasticity of Skin Epithelial Cells in Wound Healing and Tumorigenesis

Cellular differentiation, the fundamental hallmark of cells, plays a critical role in homeostasis. And stem cells not only regulate the process where embryonic stem cells develop into a complete organism, but also replace ageing or damaged cells by proliferation, differentiation and migration. In characterizing distinct subpopulations of skin epithelial cells, stem cells show large heterogeneity and plasticity for homeostasis, wound healing and tumorigenesis. Epithelial stem cells and committed progenitors replenish each other or by themselves owing to the remarkable plasticity and heterogeneity of epidermal cells under certain circumstance. The development of new assay methods, including single-cell RNA sequence, lineage tracing assay, intravital microscopy systems and photon-ablation assay, highlight the plasticity of epidermal stem cells in response to injure and tumorigenesis. However, the critical mechanisms and key factors that regulate cellular plasticity still need for further exploration. In this review, we discuss the recent insights about the heterogeneity and plasticity of epithelial stem cells in homeostasis, wound healing and skin tumorigenesis. Understanding how stem cells collaborate together to repair injury and initiate tumor will offer new solutions for relevant diseases. Schematic abstract of cellular heterogeneity and plasticity of skin epithelial cells in wound healing and tumorigenesis.

The Skin in Cowden Syndrome

Cowden syndrome (CS) is an autosomal dominant condition caused by mutations in the phosphatase and tensin homolog (PTEN) gene, and is characterized by multiple hamartomas and a predisposition to malignant tumors. Characteristic skin lesions include trichilemmomas, acral keratosis, mucocutaneous neuromas, oral papillomas, and penile macules, and are often the first clues to the underlying diagnosis. Here, we discuss the mucocutaneous manifestations of CS, differential diagnoses of genetic causes of each cutaneous finding, genetic analyses for patients with skin manifestations, management of patients with CS, and potential new targeted therapies for CS.

A Rare Case of Trichilemmal Carcinoma: Histology and Management

Trichilemmal carcinoma (TC) is a rare cutaneous tumor thought to be derived from the follicular outer root sheath (ORS). It often manifests as a nondescript skin-colored or pink papule on the hair-bearing, sun-exposed anatomic sites of elderly patients. Trichilemmal carcinoma shows many histologic features reminiscent of follicular ORS-notably, its glycogen-rich clear cells, trichilemmal keratinization, and similar immunostaining profile. Historically, it has been described as following a relatively indolent clinical course, but cases of recurrence, local aggression, and distant metastases have recently been elucidated. Here, we report the case of a 66-year-old male patient who presented with an asymptomatic, erythematous plaque on his neck; biopsy confirmed a diagnosis of TC. The patient deferred Mohs micrographic surgery in favor of wide local excision and was treated successfully with 3-mm margins. Salient histopathologic features, treatment modalities, and management recommendations are discussed.

Current Diagnosis and Treatment Options for Cutaneous Adnexal Neoplasms with Follicular Differentiation

Neoplasms derived from follicular tissue are extremely rare. Clinically, they are reported as non-symptomatic, slow-growing nodules. These lesions are mainly benign, but the malignant type can occur. Mainly middle-aged people (50-60 years of age) are affected. These carcinomas are mainly localized on the head and neck or torso. They can be locally aggressive and infiltrate surrounding tissue and metastasize to regional lymph nodes. In the minority of cases, distant metastases are diagnosed. Quick and relevant diagnosis is the basis of a treatment for all types of tumors. The patient's life expectancy depends on multiple prognostic factors, including the primary tumor size and its mitotic count. Patients should be referred to a specialized skin cancer center to receive optimal multidisciplinary treatment. This article tries to summarize all the information that is currently available about pathogenesis, diagnosis, and treatment methods of follicular tumors.

Trichofolliculoma of the Palpebral Conjunctiva: A Case Report

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Birt-Hogg-Dubé syndrome

Birt–Hogg–Dubé syndrome (BHD) is a rare inherited autosomal dominant disorder caused by germline mutations in the tumour suppressor gene FLCN, encoding the protein folliculin. Its clinical expression typically includes multiple pulmonary cysts, recurrent spontaneous pneumothoraces, cutaneous fibrofolliculomas and renal tumours of various histological types. BHD has no sex predilection and tends to manifest in the third or fourth decade of life. Multiple bilateral pulmonary cysts are found on chest computed tomography in >80% of patients and more than half experience one or more episodes of pneumothorax. A family history of pneumothorax is an important clue, which suggests the diagnosis of BHD. Unlike other cystic lung diseases such as lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis, BHD does not lead to progressive loss of lung function and chronic respiratory insufficiency. Renal tumours affect about 30% of patients during their lifetime, and can be multiple and recurrent. The diagnosis of BHD is based on a combination of genetic, clinical and/or skin histopathological criteria. Management mainly consists of early pleurodesis in the case of pneumothorax, periodic renal imaging for tumour detection, and diagnostic work-up in search of BHD in relatives of the index patient.

Birt–Hogg–Dubé syndrome is a rare genetic disorder characterised by multiple lung cysts, recurrent pneumothoraces, skin lesions and kidney tumours. As the presenting symptoms may be respiratory, chest physicians should be able to identify this disease.https://bit.ly/2xsOTuk

Are clinicians successful in diagnosing cutaneous adnexal tumors? a retrospective, clinicopathological study

Background/aim

Cutaneous adnexal tumors (CAT) are rare tumors originating from the adnexal epithelial parts of the skin. Due to its clinical and histopathological characteristics comparable with other diseases, clinicians and pathologists experience difficulties in its diagnosis.We aimed to reveal the clinical and histopathological characteristics of the retrospectively screened cases and to compare the prediagnoses and histopathological diagnoses of clinicians.

Materials and methods

The data of the last 5 years were scanned and patients with histopathological diagnosis of CAT were included in the study.

Results

A total of 65 patients, including 39 female and 26 male patients aged between 8 and 88, were included in the study. The female to male ratio was 1.5, and the mean age of the patients was 46.15 ± 21.8 years. The benign tumor rate was 95.4%, whereas the malignant tumor rate was 4.6%. 38.5% of the tumors were presenting sebaceous, 35.4% of them were presenting follicular, and 18.5% of them were presenting eccrine differentiation. It was most commonly seen in the head-neck region with a rate of 66.1%. When clinical and histopathological prediagnoses were compared, prediagnoses and histopathological diagnoses were compatible in 45% of the cases. Most frequently, it was the basal cell carcinoma, epidermal cyst, and sebaceous hyperplasia identified in preliminary diagnoses.

Conclusion

Cutaneous adnexal tumors are very important, as they can accompany different syndromes and may be malignant. Due to difficulties in its clinical diagnosis, histopathological examination must be performed from suspicious lesions for definitive diagnosis.

Trichoblastomas Mimicking Basal Cell Carcinoma: The Importance of Identification and Differentiation

Trichoblastoma is a rare, slow-growing, benign cutaneous tumor derived from follicular germinative cells. Trichoblastoma commonly appears as an asymptomatic, symmetrical, well-circumscribed, skin-colored to brown or blue-black papule or nodule. It may appear clinically and histologically similar to basal cell carcinoma, making its diagnosis challenging. Even on dermoscopy, it is challenging to differentiate trichoblastoma from basal cell carcinoma. In practice, it is important to differentiate the two, because the choice of treatment and resulting prognosis differ between the lesions. Surgical biopsy to analyze histopathological and immunohistochemical differences is the gold standard for diagnosing and differentiating trichoblastoma from basal cell carcinoma. Trichoblastoma typically has a favorable prognosis, with a low incidence of recurrence, progression or association with malignancy. This paper provides a review of the epidemiology, clinical presentation, dermoscopy, histology, immunochemistry, treatment, and prognosis of trichoblastoma.

Dermatopathology of Cutaneous Cystic Lesions: A Practical Review With Diagnostic Clues and Pitfalls

BACKGROUND

Cystic lesions are common in the daily practice of dermatologists and dermatopathologists, and in most cases, a straightforward diagnosis can be done. Yet, some variants and situations may cause diagnostic problems or carry prognostic and/or systemic implications.

OBJECTIVE

To review the histopathological features of the most frequent cystic lesions, either true cysts or pseudocysts, and provide some clues and pitfalls to bear in mind for troublesome situations such as solid-cystic tumors; uncommon variants; incidental findings; artifactual, reactive, or infectious cavities; cysts as a warning of systemic and hereditary diseases; and malignant cystic tumors, either primary or metastatic.

METHODS

The histopathological diagnostic criteria of most cystic lesions and their potential caveats will be discussed, offering some diagnostic clues.

RESULTS

Cystic lesions of the skin can primarily be classified into true cysts and pseudocysts. The most frequent pseudocysts are sinus pilonidalis and mucin-filled cavities. True cysts can be divided according to their epithelial origin or differentiation into epidermal/pilar cysts, cysts from glandular appendages, and from embryonic remnants. Diagnostic dilemmas and possible pitfalls in cystic lesions are reviewed, offering some keys to solve them.

CONCLUSIONS

Knowledge of the histopathology of cystic lesions contributes to their correct diagnosis, improving the management of patients.

Solitary fibrofolliculoma of the upper eyelid in a 68-year old female: a case report

BACKGROUND

Fibrofolliculoma is a benign, perifollicular, connective tissue tumor, and it usually arises in the form of multiple lesions, but rarely as a solitary lesion. We report a case of solitary fibrofolliculoma on the eyelid.

CASE PRESENTATION

A 68-year-old female presented with an asymptomatic mass on the right upper eyelid. The lesion appeared as a flesh-colored, dome-shaped, smooth nodule being the size of 5 × 5 × 4 mm, with eyelashes protruding from the surface, and located on the upper lid margin. Shave excision was performed, and the diagnosis of fibrofolliculoma was confirmed finally through histological exam.

CONCLUSIONS

Solitary fibrofolliculomas rarely arises on the eyelid. However, it should be suspected when a flesh-colored and doom-shaped lesion of the eyelid is encountered. The benign tumor on the lid margin can be removed by shave biopsy.

Trichoblastic Carcinosarcoma Arising From the Vagina: A Case Report With Comprehensive Immunophenotypic Analysis

A 54-year-old woman presented with abdominal pain. Magnetic resonance imaging revealed an upper vaginal mass with no pelvic side wall involvement, nodal, or distant metastasis. Radical hysterectomy was performed. Histology showed trichoblastic carcinoma with hair follicle structures and malignant sarcomatous and carcinomatous components. Hair follicular differentiation was confirmed by positivity to hair follicle markers (Bcl-2, TLE1, CD56/NCAM, and TDAG51) and presence of CD10-positive trichogenic stroma. The tumor involved the vaginal muscularis only (FIGO [International Federation of Gynecology and Obstetrics] stage I) and was excised with clear margins. The patient remained disease free at 3-month follow-up. This is the first case of cutaneous-type carcinosarcoma reported in the vagina, highlighting the difference in histology, immunophenotype, and behavior compared with gynecologic carcinosarcomas.

Basaloid tumors arising from seborrheic keratosis: Malignant basal cell carcinoma or benign basaloid follicular hamartomatous proliferation?

BACKGROUND

Basaloid tumors arising from seborrheic keratosis (SK) that resembled basal cell carcinoma (BCC) were infrequently observed in our patients. They also exhibited morphologic features similar to those of trichoblastoma or basaloid follicular hamartoma.

METHODS

We retrospectively collected cases of SK with basaloid tumors from 2001 to 2017. Ten cases of BCC, five of nevus sebaceus with trichoblastoma, five of trichoblastoma, and five of trichoepithelioma were included as controls. Tumor-associated antigens Bcl-2, CD10, PHLDA1, and CK20 were tested. Antigenic markers CD34 and CD10 were used to analyze peritumoral stroma features and Ki-67 and pHH3 to measure the mitotic activity.

RESULTS

Ten cases of SK with basaloid tumors were found and all located in non-sun-exposed areas, including five men and five women, with a mean age of 61 years. A distinct PHLDA1 staining was not observed. The staining patterns of basaloid tumor lobules associated with SK were similar to the benign control group. Bcl-2 staining in the tumor lobules was mostly negative. Peritumoral CD10 stain and CK20-positive Merkel cells in the lobules were observed and the mitotic counts were low.

CONCLUSION

Basaloid tumors arising from SK are not always BCC. They were all benign follicular hamartomatous proliferation in this case series.

Histogenesis of Merkel Cell Carcinoma: A Comprehensive Review

Merkel cell carcinoma (MCC) is a primary neuroendocrine carcinoma of the skin. This neoplasia features aggressive behavior, resulting in a 5-year overall survival rate of 40%. In 2008, Feng et al. identified Merkel cell polyomavirus (MCPyV) integration into the host genome as the main event leading to MCC oncogenesis. However, despite identification of this crucial viral oncogenic trigger, the nature of the cell in which MCC oncogenesis occurs is actually unknown. In fact, several hypotheses have been proposed. Despite the large similarity in phenotype features between MCC tumor cells and physiological Merkel cells (MCs), a specialized subpopulation of the epidermis acting as mechanoreceptor of the skin, several points argue against the hypothesis that MCC derives directly from MCs. Alternatively, MCPyV integration could occur in another cell type and induce acquisition of an MC-like phenotype. Accordingly, an epithelial as well as a fibroblastic or B-cell origin of MCC has been proposed mainly based on phenotype similarities shared by MCC and these potential ancestries. The aim of this present review is to provide a comprehensive review of the current knowledge of the histogenesis of MCC.

Trichoadenoma of the Upper Eyelid Mimicking Comedo-Like Lesions

The purpose of this report is to detail the unique occurrence of comedo-like trichoadenoma of the upper eyelid. A 54-year-old man underwent surgical resection of the lesions of the left upper eyelid that were suspected to be dilated pores. The lesions were studied with histopathological examination. Histopathology showed lesions in the dermis and epidermis containing keratinous cysts surrounded by interstitial edema and infiltration of lymphocytes. The lesions were finally diagnosed as trichoadenoma.

Management of 3 Proliferating Pilar Tumors: Definition, Differential Diagnosis, and Treatment Options

A proliferating pilar tumor is a rare skin neoplasm that arises from the outer root sheath of a hair follicle. Presentation varies widely, as the tumor can be benign or malignant and has a high probability of recurring after excision. We report our experience managing 3 proliferating pilar tumors with different clinical presentations and pathology findings at Hospital de San José, Bogota, Colombia.

Malignant proliferating trichilemmal tumour

Proliferating trichilemmal tumours are benign but locally aggressive skin neoplasms arising from hair follicles. Rarely, they can become malignant and must be appropriately managed to prevent recurrence and metastasis. One must have a low threshold for diagnosing this rare neoplasm.

Birt-Hogg-Dubé Syndrome: A Review of Dermatological Manifestations and Other Symptoms

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant genodermatosis with malignant potential characterized by cutaneous and extracutaneous stigmata. Aberrations in the folliculin (FLCN) gene, which is located on chromosome 17, have been discovered in individuals with this condition. Over 150 unique mutations have been identified in BHD. The skin lesions associated with this condition include fibrofolliculomas, trichodiscomas, perifollicular fibromas, and acrochordons. Extracutaneous features of the syndrome typically include the lung (spontaneous pneumothorax and cysts) and the kidney (neoplasms). The only malignancies associated with BHD are renal cancers; however, other tumors have been observed in individuals with BHD. In this article, the skin lesions associated with this condition are reviewed, lung and renal manifestations associated with this syndrome are presented, and malignancies occurring in these patients are summarized.

Histologic Mimics of Basal Cell Carcinoma

CONTEXT

- Basal cell carcinoma (BCC) is the most common human malignant neoplasm and is a frequently encountered diagnosis in dermatopathology. Although BCC may be locally destructive, it rarely metastasizes. Many diagnostic entities display morphologic and immunophenotypic overlap with BCC, including nonneoplastic processes, such as follicular induction over dermatofibroma; benign follicular tumors, such as trichoblastoma, trichoepithelioma, or basaloid follicular hamartoma; and malignant tumors, such as sebaceous carcinoma or Merkel cell carcinoma. Thus, misdiagnosis has significant potential to result in overtreatment or undertreatment.

OBJECTIVE

- To review key features distinguishing BCC from histologic mimics, including current evidence regarding immunohistochemical markers useful for that distinction.

DATA SOURCES

- Review of pertinent literature on BCC immunohistochemistry and differential diagnosis.

CONCLUSIONS

- In most cases, BCC can be reliably diagnosed by histopathologic features. Immunohistochemistry may provide useful ancillary data in certain cases. Awareness of potential mimics is critical to avoid misdiagnosis and resulting inappropriate management.

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.

Contribution of health care factors to the burden of skin disease in the United States

The American Academy of Dermatology has developed an up-to-date national Burden of Skin Disease Report on the impact of skin disease on patients and on the US population. In this second of 3 manuscripts, data are presented on specific health care dimensions that contribute to the overall burden of skin disease. Through the use of data derived from medical claims in 2013 for 24 skin disease categories, these results indicate that skin disease health care is delivered most frequently to the aging US population, who are afflicted with more skin diseases than other age groups. Furthermore, the overall cost of skin disease is highest within the commercially insured population, and skin disease treatment primarily occurs in the outpatient setting. Dermatologists provided approximately 30% of office visit care and performed nearly 50% of cutaneous surgeries. These findings serve as a critical foundation for future discussions on the clinical importance of skin disease and the value of dermatologic care across the population.

Birt-Hogg-Dubé Syndrome - report of two cases with two new mutations

INTRODUCTION

Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant genodermatosis characterized by cutaneous fibrofolliculomas and/or trichodiscomas, lung cysts, spontaneous pneumothorax and renal tumors. However, its clinical expression is highly variable. This syndrome is caused by germline mutations in the folliculin gene (FLCN) on chromosome 17p11.2.

MAIN OBSERVATIONS

Two men, 60 and 39-year-old, presented with a several year history of asymptomatic whitish papules scattered over the face and neck. Skin biopsies revealed fibrofolliculomas. The clinical diagnosis of BHDS was corroborated by identification of new heterozygotic mutations in FLCN gene, in exon 6 (C.573_574delinsT) and in exon 9 (c.1015C>T), respectively. Computed tomography scan of the thorax and abdomen showed pulmonary cysts with no suspicious kidneys lesions, and, in the case of the second patient, a mass in left adrenal gland. Laparoscopic left adrenalectomy was performed and histopathological examination was compatible with a malignant perivascular epithelioid cell tumor.

CONCLUSIONS

The presence of multiple fibrofolliculomas should raise the suspicion of BHDS. Patients with this syndrome, regardless of the detected mutation, should be carefully monitored to ensure that potentially serious disease-related conditions can be detected early.

Birt-Hogg-Dubé syndrome: a case report and a review of the literature

Background: Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant inherited syndrome caused by mutations in the folliculin coding gene (FLCN). The clinical manifestations of the syndrome involve the skin, lungs, and kidneys. Because of the rarity of the syndrome, guidelines for diagnosis and management of the patients with BHDS are lacking.

Objective: To present a case story and a review of the literature on BHDS in order to give an update on genetics, clinical manifestations, diagnosis, treatment, prognosis and follow-up strategies.

Design: Literature review and case story.

Results: A PubMed and Embase search identified 330 papers. BHDS is characterized by small benign tumors in the skin, spontaneous pneumothoraces caused by cysts in the lungs and a seven-fold increased risk of renal cancer. A case story of a young female patient presenting with pneumothorax and a family history of recurrent pneumothoraces in many relatives illustrates how the history and the diagnostic work up resulted in a diagnosis of BHDS.

Conclusion: BHDS is a rare inherited disorder. In patients with spontaneous pneumothorax or cystic lung disease without any obvious explanation, BHDS should be considered. Concomitant skin manifestations, a family history of familiar pneumothorax, renal cancers and skin manifestations supports the suspicion of BHDS. Early diagnosis is important in order to subject patients to systematic screening for renal cancers. A radiological surveillance strategy for renal cancer is proposed.