Hidradenoma Papilliferum: A Clinicopathologic Study of 264 Tumors From 261 Patients, With Emphasis on Mammary-Type Alterations

Immunohistochemical and Molecular Characteristics of Anogenital Papillary Hidradenomas

BACKGROUND

Papillary hidradenomas (PHs) of the anogenital region are uncommon tumors whose immunohistochemical and molecular profile have been infrequently studied.

MATERIAL AND METHODS

We studied 15 PHs by next-generation sequencing and 10 immunohistochemical markers (PAX8, GATA3, HER2, MSH6, PMS2, estrogen, progesterone and androgen receptors, CK14, and NKX3.1).

RESULTS

All cases expressed GATA3, whereas none expressed PAX8, and rare tumor cells were NKX3.1-positive. Almost all cases expressed estrogen receptors (ER), progesteron receptors (PR), and androgen receptors (AR). CK14 was expressed by myoepithelial cells, whereas only rarely by the epithelial tumor cells. HER2 showed no significant expression. Immunohistochemical expression for the mismatch repair proteins showed persistence in all cases. Molecular analysis often showed PIK3CA mutations, as well as KRAS , SMO , and MAP2K1 mutations.

CONCLUSION

Anogenital PHs frequently harbor PIK3CA mutations and show a PAX8-, GATA3/ER/PR/AR + immunohistochemical profile.

Digital Papillary Adenocarcinoma in Nonacral Skin: Clinicopathologic and Genetic Characterization of 5 Cases

Digital papillary adenocarcinoma (DPA) is a rare sweat gland neoplasm that has exceptionally been reported outside acral locations. Recently, human papillomavirus 42 was identified as the main oncogenic driver of DPA. Herein, we report 5 tumors arising in extra-acral locations predominantly in the female anogenital skin. Four patients were female and 1 patient was male. The mean age at the diagnosis time was 65 years (range: 55 to 82 y). Tumors were located on the vulva (n=3), perianal area (n=1), and forearm (n=1). Histologically, all tumors were lobular and mainly solid and composed of sheets of cells with rare focal papillae and frequent glandular structures in a "back-to-back" pattern and lined by atypical basophilic cells. Immunohistochemistry showed diffuse positivity for SOX10. Epithelial membrane antigen and carcinoembryonic antigen highlighted the luminal cells and staining for p63 and p40 revealed a consistent and continuous myoepithelial component around glandular structures. Follow-up was available in 3 cases (mean duration: 12 mo [range: 8 to 16 mo]). One patient developed local recurrence and 1 experienced regional lymph node metastases. HPV Capture Next-generation sequencing revealed the presence of the HPV42 genome in all samples. Viral reads distributions were compatible in the 5 cases with an episomal nature of the viral genome, with a recurrent deletion in the E1 and/or E2 open reading frames. In conclusion, this study demonstrates that digital DPA may rarely present in nonacral locations mainly in the female anogenital area, usually with a more solid pattern as compared with those cases presenting on the digits and it is also associated with HPV42.

Current Diagnosis and Treatment Options for Cutaneous Adnexal Neoplasms with Apocrine and Eccrine Differentiation

Adnexal tumors of the skin are a rare group of benign and malignant neoplasms that exhibit morphological differentiation toward one or more of the adnexal epithelium types present in normal skin. Tumors deriving from apocrine or eccrine glands are highly heterogeneous and represent various histological entities. Macroscopic and dermatoscopic features of these tumors are unspecific; therefore, a specialized pathological examination is required to correctly diagnose patients. Limited treatment guidelines of adnexal tumor cases are available; thus, therapy is still challenging. Patients should be referred to high-volume skin cancer centers to receive an appropriate multidisciplinary treatment, affecting their outcome. The purpose of this review is to summarize currently available data on pathogenesis, diagnosis, and treatment approach for apocrine and eccrine tumors.

Vulvar apocrine hidradenocarcinoma arising in a hidradenoma papilliferum-A case report

Hidradenoma papilliferum (HP) is a benign adnexal neoplasm of the vulva that typically presents as a unilateral, flesh-colored papule in the labium majus in middle-aged Caucasian women. It is considered to be a close counterpart of the intraductal papilloma of the breast. Malignant transformation is rare with few reports in the literature. We present a case of vulvar mammary-type apocrine hidradenocarcinoma arising in an HP.

Extramammary Paget disease of the vulva

Extramammary Paget disease (EMPD) is a rare neoplasm with uncertain histogenesis, usually presenting in the anogenital area, most commonly in the vulva. The disease is characterized by slow grow and high recurrence rates. This article reviews the epidemiological, clinical, morphological, genetic and treatment features of EMPD of the vulva reported in recent years.

Lesions of anogenital mammary-like glands: Four cases including novel pathologic and immunohistochemical observations

Anogenital mammary-like glands, formerly described as ectopic breast tissue, are currently considered to be normal histologic components of the anogenital region. Anogenital mammary-like glands can give rise to many lesions identical to counterparts in the native female breast. We describe four cases of such lesions, including fibroadenoma, gynecomastia-like hyperplasia, and ectopic mammary-type tissue with a spectrum of usual ductal hyperplasia, apocrine metaplasia, adenosis, and pseudolactational change. All four cases occurred in young women (ages 29-38) who presented with vulvar or perianal masses. Similar to previously reported cases, these lesions shared histologic and immunohistochemical characteristics identical to native female breast lesions. Novel findings in our cases included (1) the first case of gynecomastia-like change to be reported in the perianal area of a female, (2) Immunohistochemical staining identifying a 3-layered epithelium characterized by a population of CK14 and CK5/6 positive and hormone receptor negative superficial luminal cells, and (3) diffuse, strong positivity for GATA3 in all cases. Our study adds to the literature on these rare lesions and highlights findings which may be useful in understanding the pathogenesis and improving the diagnosis of anogenital mammary-like gland lesions.

Syringocystadenoma Papilliferum of the Anogenital Area and Buttocks: A Report of 16 Cases, Including Human Papillomavirus Analysis and HRAS and BRAF V600 Mutation Studies

Syringocystadenoma papilliferum (SCAP) is a benign tumor most commonly located on the head and neck area often associated with nevus sebaceus. In its usual location, the human papillomavirus (HPV) DNA and mutations in the RAS/mitogen-activated protein kinase signaling pathway have been detected in SCAP. We studied 16 cases of SCAP in the anogenital areas and buttock where this neoplasm is rare and attempted to find out whether SCAP in these sites have different histopathological and molecular biological features. It seems that there is no significant difference between the morphology of anogenital SCAP and SCAP in other locations. Several tumors in our cohort demonstrated features resembling those seen in warts, but HPV DNA was not found in these lesions. On the contrary, we identified DNA of HPV high-risk types in some tumors without HPV-related morphology. Our study confirms the role of HRAS and BRAF V600 mutations in the pathogenesis of SCAP, including SCAP in the anogenital areas and buttock.

[Anal and vulvar hidradenoma papilliferum are similar: A study of 14 cases]

INTRODUCTION

Hidradenoma papilliferum (HP) is an adenomatous proliferation of mammary-like glands. These glands are located preferentially on the vaginal labia, the perineum and the anal skin. About ninety percent of HP occur on the vulva, with anal localization being much less common.

AIM OF THE STUDY

To analyze the clinical and histological characteristics of anal HP and compare them to those seen on the vulva based on the literature.

METHOD

A monocentric retrospective analysis (in the medical and surgical proctology department of the Saint-Joseph Hospital Group, Paris) of patients for whom a diagnosis of anal HP was made based on pathological analysis of a resected sample.

RESULTS

A total of 14 female patients were included between 2012 and 2018. The mean age was 48.2 years (22-70). The tumor, single in all cases, was asymptomatic with very slow progression. It was located on the anal skin in all patients. It generally consisted of a round nodule measuring under 1cm that was barely prominent, translucent, depressible and mobile. In 15% of patients the tumor was ulcerated. Histologically, the tumor displayed the usual characteristics of HP. Only one relapse was seen, six years after resection.

CONCLUSION

The clinical and histological aspects of anal HP are the same as those of the vulva, which are better documented, namely a small, rounded, pink, translucent or bluish, and mobile tumor, with a smooth surface, and more rarely ulceration or budding, and in most cases asymptomatic. All HP were diagnosed in women and were located at the anal margin. Histopathological examination of an excised sample confirms the diagnosis and rules out a malignant tumor. The frequency of anal HP may be underestimated.

Several genotypes, one phenotype: PIK3CA/AKT1 mutation-negative hidradenoma papilliferum show genetic lesions in other components of the signalling network

About 60-70% of hidradenoma papilliferum (HP), a benign tumour of the anogenital region, were recently described to harbour mutations in major driver genes of the PI3K/AKT/MAPK-signalling pathways. However, the underlying genetic defects of the non-mutant cases are still unknown. Using a 409 gene panel, we employed targeted next generation sequencing to investigate the mutational landscape in a cohort of seven PI3K/AKT-negative cases and five cases with known hotspot mutations in either PIK3CA or AKT1. In total, we identified 29 mutations in 22 of 409 genes. The four cases with PIK3CA hotspot mutations carried no or only few additional mutations. The AKT1 hotspot mutated case harboured additional mutations in four genes (SYNE1, ADAMTS20, EP400 and CASC5). At least two of these genes are involved in or contribute to the PI3K/AKT-pathway. In the seven non-hotspot mutated cases we observed 18 mutations. Each case carried at least one mutation in a gene contributing to or involved in PI3K/AKT-signalling. Affected genes were PIK3CA (n=1, non-hotspot mutation), PIK3R1 (n=3), SYNE1, AR, IL6ST, PDGFRB, KMT2C, AR, BTK, DST, KAT6A, BRD3, RNF213, USP9X, ADGRB3, MAGI1, and IL7R (each gene mutated once). The identified PIK3CA and PIK3R1 mutations lead to constitutive activated PI3K/AKT-signalling. In conclusion, we demonstrate the genetic basis of HP in all cases. Our data suggest that tumourigenic alterations in the PI3K/AKT-pathway are indispensable in HP and establish a homogenous morphomolecular entity with a functionally converging and selecting tumourigenic mechanism.

A Case of Postpartum Anogenital Mammary-Like Gland Tumor with Focal Lactational Features: A Nomenclature Issue

Mammary-like glands (MLG) are considered to be a normal constituent of the anogenital region and can give rise to tumors with variable morphology that may be difficult to classify. We present a case of an anogenital mammary-like gland tumor in a breastfeeding woman showing morphological variation with lactational change, an unusual finding. We discuss the differing terminology used to report these tumors and the variation in assignment of their origin to MLG or ectopic breast tissue.

Hidradenoma papilliferum: an unusual benign perianal tumour

Hidradenoma papilliferum is an uncommon benign tumour that is located in the anogenital region of middle-aged women. They are usually only diagnosed after excision and are thought to arise from anogenital mammary-like glands. We present the case of a young woman who noticed a slow growing perianal lump which caused minimal symptoms.

[Fibroepithelial tumors of the anogenital mammary-like glands]

Mammary-like glands are a normal anatomical component of the anogenital region. The tumors occurring in them morphologically mimic the similar diseases of the breast. The paper presents a case of vulvar fibroadenoma with leaf-like outgrowths and apocrine metaplasia in a 38-year-old female patient. It describes the clinical and morphological characteristics of fibroadenomas and benign phyllodes tumors in the anogenital region.

[Anogenital mammary-like glands and related lesions. Part 1. Benign tumors and tumor-like disorders]

Anogenital mammary-like glands represent a normal anatomic constituent of the anogenital area and may give rise to many benign and malignant tumors that morphologically mimic similar breast diseases. The literature review is complemented by a description of 286 cases of benign tumors and tumor-like processes in the mammary-like glands. The paper presents the clinical and morphological characteristics of papillary hidradenoma, fibroadenoma, benign phyllodes tumor, lactating adenoma, sclerosing adenosis, pseudoangiomatous stromal hyperplasia, etc.

Molecular alterations in lesions of anogenital mammary-like glands and their mammary counterparts including hidradenoma papilliferum, intraductal papilloma, fibroadenoma and phyllodes tumor

Lesions affecting anogenital mammary-like glands (AGMLG) are histopathologically very similar to those seen in the breast but whether this morphological similarity is also reflected at the genetic level is unknown. To compare the underlying molecular mechanisms in lesions of AGMLG and their mammary counterparts, we analyzed the mutational profile of 16 anogenital neoplasms including 5 hidradenomas papilliferum (HP), 1 lesion with features of HP and fibroadenoma (FA), 7 FA, 3 phyllodes tumors (PhT)) and 18 analogous breast lesions (6 intraductal papillomas (IDP), 9 FA, and 3 PhT) by high-coverage next generation sequencing (NGS) using a panel comprising 50 cancer-related genes. Additionally, all cases were analyzed for the presence of a mutation in the MED12 gene. All detected mutations with allele frequencies over 20% were independently validated by Sanger sequencing (concordance: 100%). Mutations in PIK3CA, AKT1, MET, ABL1 and TP53 genes were found in lesions of AGMLG and also their mammary counterparts. The PI3K-AKT cascade plays a role in tumors arising at both sites. It appears that some histopathologically similar anogenital and breast lesions develop along similar molecular pathways.

PIK3CA and AKT1 mutations in hidradenoma papilliferum

AIMS

Hidradenoma papilliferum (HP) is a benign vulvar neoplasm that arises from anogenital mammary-like glands, and its morphology is similar to mammary intraductal papilloma. The aim of this study was to investigate oncogenic mutations involved in the tumourigenesis of HP. We focused specifically on PIK3CA and AKT1 mutations, which are both reported to be detected in 33% of mammary intraductal papillomas.

METHODS

In total, seven HP cases were analysed. Clinicopathological analyses and immunohistochemistry for oestrogen receptor, p63, smooth muscle actin (SMA), p53 and β-catenin were performed. Furthermore, PIK3CA, AKT1, BRAF and KRAS hot spot mutations were examined by Sanger sequencing.

RESULTS

Morphologically, all HPs had a papillary and tubular architecture with a biphasic pattern of epithelial and myoepithelial cells. Immunohistochemistry revealed that oestrogen receptor expression was restricted to epithelial cells, whereas p63 and SMA were exclusively expressed in myoepithelial cells. The patterns of p53 and β-catenin immunostaining suggested wild-type genotypes. Direct sequencing revealed the presence of somatic PIK3CA mutations (Ex9. c.1633G>A, p.E545K and Ex20. c.3140A>G, p.H1047R) in two of the HPs and an AKT1 (c.49G>A, p.E17K) mutation in one. BRAF and KRAS mutations were not found in any of the HP cases.

CONCLUSIONS

PIK3CA and AKT1 are frequently mutated in HP tumours (29% and 14%, respectively). PIK3CA/AKT1 pathway alterations in HP further support the hypothesis that HP is the vulvar (anogenital mammary-like gland) analogue of breast intraductal papilloma.