Genetics of adnexal tumors: An update.

Cutaneous adnexal tumors form a vast heterogeneous group that include frequent entities that are mostly benign, as well as rare tumors that are occasionally malignant. In contrast to cutaneous tumors arising from the interfollicular epidermis that develop as a result of accumulation of UV-induced DNA damage (basal cell carcinoma, squamous cell carcinoma), the oncogenesis of adnexal tumors is related to a broad spectrum of genetic mechanisms (e.g., point mutation, fusion genes, viral integration, etc.). In this setting, specific and recurrent genetic alterations have been progressively reported, and these allow better classification of these entities. For certain of them, immunohistochemical tools are now available, enabling precise integrated histological and molecular diagnosis since certain entities are linked to well-defined alterations. In this context, we aim in this review to summarize the main molecular tools currently available for the classification of adnexal tumors.

NGS Analysis Confirms Common TP53 and RB1 Mutations, and Suggests MYC Amplification in Ocular Adnexal Sebaceous Carcinomas.

Ocular adnexal (OA) sebaceous carcinomas generally demonstrate more aggressive clinical and histopathological phenotypes than extraocular cases, but the molecular drivers implicated in their oncogenesis remain poorly defined. A retrospective review of surgical and ocular pathology archives identified eleven primary resection specimens of OA sebaceous carcinomas with adequate tissue for molecular analysis; two extraocular cases were also examined. Next-generation sequencing was used to evaluate mutations and copy number changes in a large panel of cancer-associated genes. Fluorescence in situ hybridization (FISH) confirmed MYC copy number gain in select cases, and immunohistochemistry to evaluate MYC protein expression. The commonest mutations occurred in TP53 (10/13) and RB1 (7/13). Additional mutations in clinically actionable genes, or mutations with a frequency of at least 25%, included the NF1 (3/12), PMS2 (4/12), ROS1 (3/12), KMT2C (4/12), MNX1 (6/12), NOTCH1 (4/12), PCLO (3/12), and PTPRT (3/12) loci. Low level copy number gain suggestive of amplification of the MYC locus was seen in two cases, and confirmed using FISH. MYC protein expression, as assessed by immunohistochemistry, was present in almost all sebaceous carcinoma cases. Our findings support the concept that alterations in TP53 and RB1 are the commonest alterations in sebaceous carcinoma, and suggest that MYC may contribute to the oncogenesis of these tumors.

Update on Molecular Genetic Alterations of Cutaneous Adnexal Neoplasms.

Cutaneous adnexal tumors recapitulate follicular, sweat gland, and/or sebaceous epithelia, and range from benign tumors to aggressive carcinomas. Adnexal tumors can be hallmarks for inherited tumor syndromes. Oncogenic drivers of adnexal neoplasms modulate intracellular pathways including mitogen-activated protein kinase, phosphoinositide-3-kinase, Wnt/ß-catenin, Hedgehog, nuclear factor κB, and Hippo intracellular signaling pathways, representing potential therapeutic targets. Malignant progression can be associated with tumor suppressor loss, especially TP53. Molecular alterations drive expression of specific diagnostic markers, such as CDX2 and LEF1 in pilomatricomas/pilomatrical carcinomas, and NUT in poromas/porocarcinomas. In these ways, improved understanding of molecular alterations promises to advance diagnostic, prognostic, and therapeutic possibilities for adnexal tumors.

Identification of potentially druggable molecular alterations in skin adnexal malignancies.

Skin adnexal cancers (SAC) are a heterogeneous group of rare malignancies with histological differentiation towards epithelial adnexa, which lack effective systemic treatments. The aim of this work is to identify any potentially druggable genomic alterations for possible targeted therapies. Cases of primary or recurrent/metastatic (RM) SAC between 2002 and 2014 were identified by searching the institutional cancer registration database. Histological sections of all referral cases were reviewed by a dedicated pathologist to confirm diagnosis. Immunohistochemistry was performed to assess the expression of androgen receptors (AR) and human epidermal growth factor receptor type 2 (HER2). Targeted next-generation sequencing (T-NGS) was performed to identify targetable mutations (panel of 50 genes analyzed by Cancer Hotspot Panel, Ion-Torrent Personal Genome Machine). Mutational analysis of the PTCH1 gene not present in the T-NGS panel was assessed by Sanger sequencing. A total of 45 cases with available histological samples were identified (35 primary, 10 RM). The most frequent histological type was porocarcinoma (n = 12). Globally, 14 cases (31%) were AR+ (6/10 RM, 60%; 8/35 primary, 23%). HER2 was shown as 2+ in eight of 42 (19%) cases (2/9 RM, 22%; 6/33 primary, 18%). DNA was adequate for T-NGS analysis in 25 cases. In the majority of cases (17 cases, 68%) at least one mutation in oncogenes or tumor suppressor genes was found: the most frequent ones involved TP.53 (13 cases, 76% of mutated SAC) and PIK3CA (three cases, 18%). The rate of PTCH1 mutation was 30%. These findings support the use of molecular screening in patients with advanced SAC.

Distinct Biological Types of Ocular Adnexal Sebaceous Carcinoma: HPV-Driven and Virus-Negative Tumors Arise through Nonoverlapping Molecular-Genetic Alterations.

PURPOSE: Ocular adnexal (OA) sebaceous carcinoma is an aggressive malignancy of the eyelid and ocular adnexa that frequently recurs and metastasizes, and effective therapies beyond surgical excision are lacking. There remains a critical need to define the molecular-genetic drivers of the disease to understand carcinomagenesis and progression and to devise novel treatment strategies. EXPERIMENTAL DESIGN: We present next-generation sequencing of a targeted panel of cancer-associated genes in 42 and whole transcriptome RNA sequencing from eight OA sebaceous carcinomas from 29 patients. RESULTS: We delineate two potentially distinct molecular-genetic subtypes of OA sebaceous carcinoma. The first is defined by somatic mutations impacting TP53 and/or RB1 [20/29 (70%) patients, including 10 patients whose primary tumors contained coexisting TP53 and RB1 mutations] with frequent concomitant mutations affecting NOTCH genes. These tumors arise in older patients and show frequent local recurrence. The second subtype [9/29 (31%) patients] lacks mutations affecting TP53, RB1, or NOTCH family members, but in 44% (4/9) of these tumors, RNA sequencing and in situ hybridization studies confirm transcriptionally active high-risk human papillomavirus. These tumors arise in younger patients and have not shown local recurrence. CONCLUSIONS: Together, our findings establish a potential molecular-genetic framework by which to understand the development and progression of OA sebaceous carcinoma and provide key molecular-genetic insights to direct the design of novel therapeutic interventions.

Epidermal Nevi and Related Syndromes - Part 2: Nevi Derived from Adnexal Structures. / Nevus epidérmicos y síndromes relacionados. Parte 2: Nevus derivados de estructuras anexiales.

Epidermal nevi are hamartomatous lesions derived from the epidermis and/or adnexal structures of the skin; they have traditionally been classified according to their morphology. New variants have been described in recent years and advances in genetics have contributed to better characterization of these lesions and an improved understanding of their relationship with certain extracutaneous manifestations. In the second part of this review article, we will look at nevi derived from the adnexal structures of the skin and associated syndromes.

Significant association between TNFAIP3 inactivation and biased immunoglobulin heavy chain variable region 4-34 usage in mucosa-associated lymphoid tissue lymphoma.

Both antigenic drive and genetic change play critical roles in the development of mucosa-associated lymphoid tissue (MALT) lymphoma, but neither alone is sufficient for malignant transformation, and lymphoma development critically depends on their cooperation. However, which of these different events concur and how they cooperate in MALT lymphomagenesis is totally unknown. To explore this, we investigated somatic mutations of 17 genes and immunoglobulin heavy chain variable region (IGHV) usage in 179 MALT lymphomas from various sites. We showed that: (1) there was a significant association between the biased usage of IGHV4-34 (binds to the carbohydrate I/i antigens) and inactivating mutation of TNFAIP3 [encoding a global negative regulator of the canonical nuclear factor-κB (NF-κB) pathway] in ocular adnexal MALT lymphoma; (2) IGHV1-69 was significantly overrepresented (54%) in MALT lymphoma of the salivary gland, but was not associated with mutation in any of the 17 genes investigated; and (3) MALT lymphoma lacked mutations that are frequently seen in other B-cell lymphomas characterized by constitutive NF-κB activities, including mutations in CD79B, CARD11, MYD88, TNFRSF11A, and TRAF3. Our findings show, for the first time, a significant association between biased usage of autoreactive IGHV and somatic mutation of NF-κB regulators in MALT lymphoma, arguing for their cooperation in sustaining chronic B-cell receptor signalling and driving oncogenesis in lymphoma development. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Secretory Carcinoma of the Skin Harboring ETV6 Gene Fusions: A Cutaneous Analogue to Secretory Carcinomas of the Breast and Salivary Glands.

Mammary analogue secretory carcinoma is a low-grade salivary gland carcinoma that exhibits analogous features to secretory carcinoma of the breast including the presence of a t(12;15) translocation resulting in the ETV6-NTRK3 gene fusion. Rare cases of purported secretory carcinoma of the skin adnexa have been reported, but their relationship to true secretory carcinoma of the breast and salivary glands is unclear, as they generally do not harbor ETV6 rearrangements. Cases of cutaneous neoplasms with histologic features identical to secretory carcinoma of the breast and salivary glands were identified from the consultation files of 3 academic medical institutions. Immunohistochemistry was performed for S100 protein, mammaglobin and STAT5a. Break-apart fluorescence in situ hybridization was used evaluate for disruption of the ETV6 gene. Six cases of cutaneous secretory carcinoma were identified. The tumors arose in 4 women and 2 men, ranging from 24 to 71 years in age (mean, 47 y). The carcinomas presented in the skin of the axilla (n=4), ventral neck (n=1), and cheek (n=1). The tumors arose in the superficial dermis in association with adnexal structures. None of the patients had a prior or concurrent breast or salivary gland tumor. They were histologically characterized by well-circumscribed but unencapsulated proliferations of bland, eosinophilic cells arranged in microcysts and follicles with intraluminal secretions. Ectopic breast or salivary gland tissue was not identified. The cases were diffusely positive for S100 protein (6 of 6), mammaglobin (6 of 6), and STAT5a (5 of 5). All 6 cases harbored rearrangements of ETV6. All tumors were treated by simple excision alone. No recurrences or metastases developed in the 2 cases with follow-up. Secretory carcinoma of the skin represents a phenotypic, immunohistochemical, and genetic counterpart to secretory carcinoma of the breast and salivary glands. This tumor entity is less anatomically restricted than previously supposed.

Transgenic mouse model of cutaneous adnexal tumors.

TMEM207 was first characterized as being an important molecule for the invasion activity of gastric signet-ring cell carcinoma cells. In order to unravel the pathological properties of TMEM207, we generated several transgenic mouse lines, designated C57BL/6-Tg (ITF-TMEM207), in which murine TMEM207 was ectopically expressed under a truncated (by ~200 bp) proximal promoter of the murine intestinal trefoil factor (ITF) gene (also known as Tff3). Unexpectedly, a C57BL/6-Tg (ITF-TMEM207) mouse line exhibited a high incidence of spontaneous intradermal tumors with histopathological features that resembled those of various human cutaneous adnexal tumors. These tumors were found in ~14% female and 13% of male 6- to 12-month-old mice. TMEM207 immunoreactivity was found in hair follicle bulge cells in non-tumorous skin, as well as in cutaneous adnexal tumors of the transgenic mouse. The ITF-TMEM207 construct in this line appeared to be inserted to a major satellite repeat sequence at chromosome 2, in which no definite coding molecule was found. In addition, we also observed cutaneous adnexal tumors in three other C57BL/6-Tg (ITF-TMEM207) transgenic mouse lines. We believe that the C57BL/6-Tg (ITF-TMEM207) mouse might be a useful model to understand human cutaneous adnexal tumors.

[Differential diagnostics of sebaceous tumors]. / Differenzialdiagnostik der Talgdrüsentumoren.

Sebaceous tumors are epithelial tumors with a differentiation towards sebaceous adnexal structures of the skin. They imitate the epithelial cells of mature sebaceous glands, sebaceous ducts, immature (embryonic) sebaceous structures or sebaceous glands that are not stimulated by hormones (mantle structures). This article explains the classification of sebaceous tumors on the basis of the normal histology of sebaceous glands. Clinical and histopathological criteria are given for the most important sebaceous tumors. The differential diagnosis of sebaceoma, sebaceous adenoma and various types of sebaceous carcinoma is emphasized. The importance of a specific diagnosis of adnexal tumors is demonstrated by tumor-associated syndromes with involvement of other organs (e.g., Muir-Torre syndrome and Birt-Hogg-Dubé syndrome). Furthermore, conceptional controversies, problems in differential diagnosis and the impact of immunohistochemical staining in the assessment of sebaceous tumors are considered.

Melanoma arising from a long-standing pigmented trichoblastoma: clinicopathologic study with complementary aCGH/mutational analysis.

Trichoblastoma is a benign cutaneous adnexal tumor, composed mostly of follicular germinative cells. Its pigmented variant is colonized by numerous dendritic melanocytes. So far, only one case in the literature describes a combination of trichoblastoma and melanoma. We report the case of a 62-year-old man who had a slow-growing mass of the left flank present since childhood. This 8-cm mass was surgically removed when it became ulcerated and associated with axillary lymph nodes. Histologically, this tumor was strictly dermal and composed of 2 intermingled components. Large sheets of atypical, proliferating epithelioid cells predominated. Dispersed solid nests or cribriform epithelial islets encased in fibrous tissue were also seen. Some nests displayed a massive colonization by pigmented dendritic melanocytes. On immunohistochemical staining, the sheets of atypical cells expressed focally but strongly S100 protein, MelanA, HMB45, and MiTF. Epithelial structures diffusely expressed pancytokeratin AE1/AE3, KL1, and pleckstrin homology-like domain, family A, member 1. Based on these results, we diagnosed an intradermal melanoma, possibly developed from dendritic melanocytes colonizing a giant pigmented trichoblastoma. Direct sequencing of the melanoma revealed a rarely described NRAS mutation c.34G>T (G12C). Array comparative genomic hybridization displayed a complex profile somewhat divergent from standard melanoma profiles. The patient died of widespread metastatic disease 8 months after initial diagnosis.

What is new in adnexal tumors of the skin?

This article reviews the recent dermatopathology literature regarding cutaneous adnexal neoplasms, with emphasis on new and underrecognized entities, "old entities" with new findings, advances in immunohistochemistry, and new findings in relation to inherited disorders associated with cutaneous adnexal neoplasms.

A clinicopathologic and molecular biologic study of patients presenting with few adnexal tumors (two to four) from the morphological spectrum of Brooke-Spiegler syndrome.

We report 11 individuals, each presenting with few (2-4) adnexal neoplasms histologically confirmed as belonging to the spectrum of lesions typical for Brooke-Spiegler syndrome (BSS) and/or multiple familial trichoepitheliomas. These include spiradenoma, cylindroma, spiradenocylindroma, and trichoblastoma variants. Our objective was to clarify whether this is merely a sporadic, albeit unusual, occurrence of multiple neoplasms in these patients or whether they are related to BSS and its phenotypic variant, multiple familial trichoepithelioma. Six patients presented with 2 neoplasms, 4 had 3 lesions and the last had 4 lesions. In none was there any family history of similar lesions. The 28 neoplasms consisted of 7 spiradenomas, 6 cylindromas, 5 spiradenocylindromas, and 11 trichoblastomas (6 trichoepitheliomas and 5 with mixed patterns). In 1 patient only with 2 spiradenomas, both tumors harbored identical CYLD sequence alterations (c.1112C>A/S371X) in the CYLD gene and both showed loss of heterozygosity on chromosome 16q. The remaining cases yielded neither germ line nor somatic alterations in CYLD. It is concluded that the presentation with few (2-4) cylindromas, spiradenomas, spiradenocylindromas, and trichoepitheliomas is a sporadic occurrence, and that these patients do not have any relationship to BSS.

Microcystic adnexal carcinoma versus desmoplastic trichoepithelioma: a comparative study.

The histologic distinction between microcystic adnexal carcinoma (MAC) and desmoplastic trichoepithelioma (dTE) can be challenging in the setting of a superficial biopsy. However, accurate diagnosis has treatment implication because the standard of care for MAC is wide local excision but more conservative care for dTE. We reviewed the histologic features of 30 MAC and 39 dTE cases and performed cytokeratin (CK) 17, CK19, and epidermal growth factor receptor (EGFR) immunostains on 20 MACs and 18 dTEs. MAC cases occurred in older patients in comparison with dTE (median, 67 years vs. 34 years). The head and neck was the most commonly involved site, 88% and 89% for MAC and dTE, respectively. In addition to features previously reported as specific for MAC, such as skeletal muscle and subcutaneous tissue invasion, perineural invasion, and ductal differentiation, we found the presence of mitotic figures to be significantly more frequent in MAC cases (P < 0.0001). In contrast, the presence of keratocyst, keratin granuloma, and calcification was significantly more frequent in dTE cases (P < 0.0001). CK19 seems to be a helpful adjunct because its expression was seen in 70% (14/20) of MAC versus 22% (4/18) of dTE cases (P = 0.0044); however, the clinical usefulness in individual cases may be limited because of the overlapping immunoprofile. CK17 and EGFR expression was seen in all the MAC and dTE cases. Low polysomy of EGFR gene was observed in only one MAC case, suggesting that molecular mechanisms other than gene amplification play a role in EGFR overexpression.

Spectrum of cutaneous and soft tissue lesions in two Carney complex patients-adnexal induction versus authentic adnexal neoplasms.

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. Additionally, 1 soft tissue myxoma was unique in the sense that it greatly resembled a cardiac myxoma, begging the question whether this could represent an embolus from the patient's cardiac myxoma. Given the large size and complexity and heterogeneity of the cutaneous lesions, the authors suggest that these may represent authentic cutaneous neoplasms accompanied by myxoid stroma and not adnexal elements induced by the stroma. However, the latter mechanism is well recognized and demonstrated by our second patient in whom adnexal-type elements in the cutaneous lesion were clearly induced by the myxoid stroma but were unusually complex by manifesting panfollicular and also sebaceous differentiation.

Gene expression profiling guiding diagnosis and therapy of rare mammary-like anogenital gland carcinomas.

Cancers derived from anogenital mammary-like glands are rare, and their identification and selection of treatment for dissemination may be difficult. We encountered two such tumors, which both presented as occult primaries with nodal and hematogenous metastases. They were studied by immunohistochemistry, HER2 receptor assay, and gene expression profiling. Both tumors had some microscopical and immunohistochemical features in common with breast cancer, but lacked estrogen and progesterone receptors. Taxane-platinum-based systemic chemotherapy did not stop progression in a male patient, in whom a developing inguinal skin lesion was the likely primary tumor. The same regimen gave partial remission in a later, female, patient. After the mammary-like, HER2 positive nature of her tumor was confirmed by gene expression profiling using CupPrint and TargetPrint assays, treatment with vinorelbine-trastuzumab induced complete remission that is maintained by trastuzumab alone for almost 4 years after initial diagnosis. Molecular and immunohistochemical characterization of these rare tumors may identify them and sometimes guide systemic chemotherapy away from a non-specific and "broad spectrum" regimen toward a targeted therapy, resulting in greater effectiveness with less side effects.

Skin-type adnexal tumor with trichoblastic germinative differentiation in the breast: a case report.

Adnexal tumors with follicular differentiation in the breast parenchyma are rarely encountered. The authors present a unique case arising in a 64-year-old woman, in whom they observed composite differentiation toward follicular germinative cells of the hair follicle with focal areas of outer root sheath differentiation and pilar-type keratinization. The histogenesis of this tumor is analyzed in light of the peculiar pathological, immunohistochemical, and molecular genetic findings.

An unusual case of turban tumor syndrome treated with total scalp excision and advancement flap and skin graft reconstruction.

We report an unusual case of aggressive turban tumor syndrome in a 38-year-old woman with nodules covering her scalp and involving her face, neck, chest, and back. To address concerns regarding hygiene of the scalp and cosmetic disfigurement, she underwent total scalp excision with advancement flap and skin graft reconstruction. Histologic examination of the scalp tumors revealed a predominance of spiradenomas, along with cylindromas and trichoepitheliomas, and tumors containing elements of all 3 of these adnexal neoplasms. We review the literature regarding turban tumor syndrome including the genetic basis for this condition, clinical features, pathology, and treatment.

Spectrum of tumors with follicular differentiation in a patient with the clinical phenotype of multiple familial trichoepitheliomas: a clinicopathological and molecular biological study, including analysis of the CYLD and PTCH genes.

We report a patient with multiple trichoepitheliomas whose biopsy material also demonstrated a range of other neoplasms with follicular differentiation, including small nodular trichoblastoma, small nodular basal cell carcinoma (BCC), and areas resembling infundibulocystic BCC/basaloid follicular hamartoma. These were all intimately associated with otherwise typical trichoepitheliomas that dominated the microscopic appearances. Peripheral blood and tumor tissues of the patient and his 2 daughters, who apparently had a milder phenotype, were studied for alterations in the CYLD and PTCH genes, but mutations or loss of heterozygosity was not found in either gene. The occurrence of multiple follicular neoplasms within a single lesion adds evidence that, although in most cases BCC and trichoblastoma are distinct lesions, the 2 neoplasms do encompass a morphological spectrum of follicular differentiation, which is probably more overtly expressed in syndromic patients.