Spiradenoma and spiradenocylindroma with an adenomatous or atypical adenomatous component: a clinicopathological study of 6 cases

Spiradenoma With Adenoid Cystic Carcinoma-like Changes: A Case Series of This Rare Variant With a Potential Diagnostic Pitfall

Spiradenomas are benign cutaneous adnexal neoplasms with sweat gland differentiation that can manifest a broad spectrum of histomorphologic appearances. While they show a characteristic histopathologic phenotype and clinical management involves surgical excision with a low risk of recurrence, there have been unusual histopathologic variants of spiradenoma reported, including cases with adenoid cystic carcinoma (ACC)-like changes. Primary cutaneous ACC is a low-grade malignancy presenting as a subcutaneous mass with the potential for local invasion, perineural invasion, and high rates of local recurrence after excision. The diagnosis of spiradenomas with ACC-like features can be challenging, especially when only the ACC-like component is present for evaluation. A retrospective analysis of 21 cases of spiradenoma with ACC-like changes were obtained from large academic institutions, was performed, and summarized below. All cases showed background of conventional spiradenoma, and the ACC-like areas represented a component in all lesions. The percentage of ACC-like component ranged from 5% to 40% in all cases. The ACC-like component was multifocal and without pleomorphism, perineural and/or vascular invasion, necrosis, or increased mitotic activity. MYB translocation and protein expression was studied in 16 cases by fluorescence in situ hybridization, polymerase chain reaction, and immunohistochemistry. All studied cases were negative for MYB / NFIB , MYB L1, and MYB F by fluorescence in situ hybridization and polymerase chain reaction and 3 cases were positive for MYB expression by immunohistochemistry. Our study expands on spiradenomas with ACC-like features that ought to be considered in the differential diagnosis of cutaneous neoplasms such as primary cutaneous ACC. Our results indicate that a thorough histopathologic inspection and strict application of well-defined histologic criteria are necessary to support the diagnosis of this unusual histopathologic variant. These tumors can be difficult to diagnose, and awareness of their histomorphologic spectrum will facilitate definitive diagnosis and avoid misdiagnosis with other conditions.

Genetic Testing in CYLD Cutaneous Syndrome: An Update

CYLD cutaneous syndrome (CCS) is an inclusive label for the inherited skin adnexal tumour syndromes Brooke–Spiegler Syndrome (BSS-OMIM 605041), familial cylindromatosis (FC – OMIM 132700) and multiple familial trichoepitheliomas (MFT-OMIM 601606). All three syndromes arise due to germline pathogenic variants in CYLD, a tumour suppressor gene (OMIM 605018). CCS is transmitted in an autosomal dominant pattern, and has variable expressivity, both of the three syndromic phenotypes, and of the severity of tumour burden. Age-related penetrance figures are not precisely reported. The first tumours typically appear during puberty and progressively accumulate through adulthood. Penetrance is typically high, with equal numbers of males and females affected. Genetic testing is important for confirmation of the clinical diagnosis, genetic counselling and family planning, including preimplantation diagnosis. Additionally, identified CCS patients may be eligible for future clinical trials of non-surgical pre-emptive interventions that aim to prevent tumour growth. In this update, we review the clinical presentations of germline and mosaic CCS. An overview of the germline pathogenic variant spectrum of patients with CCS reveals more than 100 single nucleotide variants and small insertions and deletions in coding exons, most frequently resulting in predicted truncation. In addition, a minority of patients have large deletions involving the CYLD gene, intronic pathogenic variants that affect splicing, or inversions. We discuss germline and somatic testing approaches. Somatic testing of tumour tissue, relevant in mosaic CCS, can reveal recurrently detected pathogenic variants when two or more tumours are tested. This can influence genetic testing of children, who may inherit this as a germline variant, and inform genetic counselling and prenatal diagnosis. Finally, we discuss testing technologies that are currently used, their benefits and limitations, and future directions for genetic testing in CCS.

Cutaneous eccrine inflammation and necrosis: review of inflammatory disorders affecting the eccrine apparatus including new associations

Despite being frequently overlooked during the examination of histopathological sections, eccrine sweat glands can offer clues for diagnosing various skin conditions. They provide important functions and can lead to several diseases when inflamed or injured. This review article provides information regarding eccrine physiology as well as well-established and novel entities that occur in association with eccrine gland pathology.

Primary Cutaneous Adenomyoepithelioma Ex Spiradenoma With Malignant Histologic Features, Epithelial-Myoepithelial Carcinoma Type: A First Case Report With Molecular Studies

Adenomyoepithelioma is an extremely rare primary cutaneous neoplasm. Although there is ample evidence on the existence of malignant adenomyoepithelioma in the breast, a malignant counterpart in the skin has not been documented. We report a primary cutaneous adenomyoepithelioma (pcAME) with malignant features arising from a spiradenoma in a 39-year-old female patient. The tumor was solid-cystic in appearance and entirely located in the subcutaneous tissue. Histologically, the tumor displayed foci of adenomatous changes and adenomyoepitheliomatous hyperplasia adjacent to a minute spiradenoma. Gradual increase of architectural complexity, cytologic atypia, mitotic activity, and infiltrative growth were observed in a significant portion of the neoplasm, indicative of transformation to adenomyoepithelioma and subsequently low- to high-grade salivary-type epithelial-myoepithelial carcinoma (EMCA). The intimate dual populations of ductal and myoepithelial cells were highlighted by a panel of immunohistochemical stains in all different components of the tumor. Molecular studies revealed a PIKCA3 mutation, a genetic aberration that has been documented in EMCA, particularly of breast origin. The current case documents for the first time a pcAME with malignant features arising from a spiradenoma and suggests adenomyoepithelioma ex spiradenoma as a possible tumorigenesis pathway of this rare cutaneous tumor.

Syringometaplasia: variants and underlying mechanisms

Syringometaplasia is an adaptive, benign, metaplastic cellular process that affects the eccrine ducts and glands in response to a variety of physiological or pathological stimuli. Different subtypes of syringometaplasia have been described, including the squamous, mucinous, and adenomatous types. These metaplastic changes have been reported in association with chemotherapeutic agents, as well as with a variety of skin disorders including multiple infectious, neoplastic, and inflammatory skin diseases. In this review, we attempt to shed light on the different patterns of syringometaplasia, its pathogenesis, the plethora of skin conditions in which it may be observed, and the differential diagnoses that should be considered.

Phenotype-genotype correlations for clinical variants caused by CYLD mutations

Brooke-Spiegler syndrome (BSS; OMIM 605041) is an autosomal dominant condition characterized by skin appendageal neoplasms including cylindromas, trichoepitheliomas, and/or spiradenomas. In 1996, the gene locus for BSS was mapped to 16q12-13, and, in 2000, mutations in the cylindromatosis (CYLD) gene were determined to cause BSS, familial cylindromatosis (FC; OMIM 132700) and multiple familial trichoepithelioma type 1 (MFT1; OMIM 601606). The CYLD gene encodes an enzyme with deubiquitinase activity. To date, a total of 95 different diseases-causing mutations have been published for the CYLD gene. A summary of mutations identified in Hungarian patients and a review of previously published mutations are presented in this update. The majority of the sequence changes are frameshift (48%), nonsense (27%), missense (12%) and splice-site (11%) mutations; however, two in-frame deletions have also been reported. Most mutations are located in exons 9-20. Analysis of the identified CYLD gene mutations and the observed BSS, FC and MFT1 clinical phenotypes of the patients revealed significant genotype-phenotype correlations. Elucidation of these genotype-phenotype correlations is critical for the diagnosis of these rare monogenic skin diseases. In addition, characterizing these correlations may promote the understanding of their mechanisms and may hopefully contribute to the development of future therapeutic modalities.

Spiradenocarcinoma, cylindrocarcinoma and spiradenocylindrocarcinoma: a clinicopathological study of nine cases

AIMS

To elucidate diagnostic criteria for spiradenocarcinoma, cylindrocarcinoma and spiradenocylindrocarcinoma, and to emphasize correlations between clinical behaviour and variable morphological patterns.

METHODS AND RESULTS

We investigated the clinicopathological and immunophenotypic features of nine cases. There were five men and four women, with ages ranging from 58 years to 82 years. The tumour size varied from 10 mm to 50 mm. The head and neck were most commonly involved. Three cases of spiradenocarcinoma and three cases of cylindrocarcinoma showed a salivary gland-type basal cell adenocarcinoma-like pattern, low-grade (BCAC-LG) and/or high grade (BCAC-HG). The remaining three cases of spiradenocarcinoma showed adenocarcinoma in situ, with invasive adenocarcinoma being seen in one of these cases. PAS staining revealed loss of the PAS-positive hyaline sheath in malignant zones of cylindrocarcinoma. p53 staining was variably positive in the malignant components of all cases. Follow-up was available for all patients, ranging from 5 months to 107 months. Two patients died of disease, one experienced recurrence, and one died of an unrelated cause.

CONCLUSIONS

Patients with BCAC-LG have a better prognosis. BCAC-HG is more likely to be found in cylindrocarcinoma, and its clinical behaviour seems to be more aggressive. Close follow-up for early detection of recurrence and metastases is strongly recommended.

Update of cylindromatosis gene (CYLD) mutations in Brooke-Spiegler syndrome: novel insights into the role of deubiquitination in cell signaling

Germline mutations in the cylindromatosis (CYLD) gene have been described in families with cylindromas, trichoepitheliomas, and/or spiradenomas. Brooke-Spiegler syndrome (BSS) is the autosomal dominant predisposition to skin appendageal neoplasms including cylindromas, trichoepitheliomas, and/or spiradenomas. We review the clinical features, molecular genetics, and the animal models of BSS. To date, a total of 51 germline CYLD mutations have been reported, occurring in exons 9-20, in 73 families with diverse ethnic and racial backgrounds. Of 51 mutations, 86% are expected to lead to truncated proteins. The seven missense mutations reported to date occur only within the ubiquitin (Ub)-specific protease (USP) domain of the CYLD protein and most are associated exclusively with multiple familial trichoepithelioma (MFT). CYLD functions as a tumor suppressor gene. CYLD encodes a deubiquitinating (DUB) enzyme that negatively regulates the nuclear factor (NF)-kappaB and c-Jun N-terminal kinase (JNK) pathways. CYLD DUB activity is highly specific for lysine 63 (K63)-linked Ub chains but has been shown to act on K48-linked Ub chains as well. In 2008, the CYLD USP domain was crystallized, revealing that the truncated Fingers subdomain confers CYLD's unique specificity for K63-linked Ub chains. Recent work using animal models revealed new roles for CYLD in immunity, lipid metabolism, spermatogenesis, osteoclastogenesis, antimicrobial defense, and inflammation.

Morphologic diversity of malignant neoplasms arising in preexisting spiradenoma, cylindroma, and spiradenocylindroma based on the study of 24 cases, sporadic or occurring in the setting of Brooke-Spiegler syndrome

The authors present a series of 24 malignant neoplasms arising in preexisting benign spiradenoma (20), cylindroma (2), and spiradenocylindroma (2). Nineteen patients (12 females, 7 males; age range, 41 to 92 y) had a solitary neoplasm (size range, 2.2 to 17.5 cm; median 4 cm), whereas the remaining 5 (4 females, 1 male; age range, 66 to 72 y) manifested clinical features of Brooke-Spiegler syndrome (BSS), an autosomal dominantly inherited disease characterized by widespread, small, benign neoplasms on which background larger malignant lesions appeared. Microscopically, all cases showed the residuum of a preexisting benign neoplasm. The malignant components of the lesions were variable and could be classified into 4 main patterns, occurring alone or in combination: 1) salivary gland type basal cell adenocarcinoma-like pattern, low-grade (BCAC-LG); 2) salivary gland type basal cell adenocarcinoma-like pattern, high-grade (BCAC-HG); 3) invasive adenocarcinoma, not otherwise specified (IAC-NOS); and 4) sarcomatoid (metaplastic) carcinoma. In 1 case of IAC-NOS, an in situ adenocarcinoma was also found, presumed to have evolved from an adjacent adenomatous and atypical adenomatous component. Cases harboring a sarcomatoid carcinoma featured a malignant epithelial component composed of varying combinations of BCAC-HG, BCAC-LG, IAC-NOS, or squamous cell carcinoma, whereas the sarcomatoid component appeared as either a pleomorphic or spindle-cell sarcoma. Additionally, in 2 cases there were foci of heterologous chondrosarcomatous differentiation and in 1 case there was rhabomyosarcomatous differentiation. Of the 21 patients with available follow-up (range, 3 mo-15 y; average 4.8 y; median 3.5 y), 10 were without evidence of disease, 1 was alive with metastatic disease, 1 was alive with BSS, 3 developed local recurrences, 4 had died of disease, and 2 were dead of other causes. The histologic pattern of the malignant neoplasm correlated to some extent with the clinical course. BCAC-LG neoplasms showed a less aggressive course, with local recurrences but no distant metastases, whereas the BCAC-HG neoplasms typically followed a highly aggressive course resulting in the death 3 of 6 patients with BCAC-HG. Patients with sarcomatoid carcinoma had a relatively good survival. Molecular genetic investigations revealed no mutations in the CYLD gene in the 4 sporadic cases investigated. One patient with BSS revealed a novel missense germline mutation in exon 14 (c. 1961T>A, p. V654E), whereas a living descendant of another deceased patient demonstrated a recurrent nonsense germline mutation in exon 20 (c. 2806C>T, p. R936X). Given the morphologic diversity and complexity of the neoplasms in question, we propose using a more specific terminology with the precise description of the neoplasm components, rather than generic and less informative terms such as "spiradenocarcinoma" or "carcinoma ex cylindroma."