Cuticular Poroma: A Rare Poroma Variant Simulating a Malignant Neoplasm That Often Harbors YAP1::NUTM1 Fusions Similar to Their Conventional Counterparts.

ABSTRACT: Cuticular poroma is a rare variant of poroma composed of exclusively or predominantly cuticular cells, namely of large cells with ample eosinophilic cytoplasm. We report 7 cases of this rare tumor identified among 426 neoplasms diagnosed as poroma or porocarcinoma. The patients were 4 males and 3 females, ranging in age from 18 to 88 years. All presented with a solitary asymptomatic nodule. The location included knee (2 cases), shoulder, thigh, shin, lower arm, and neck (each 1). All lesions were surgically removed. No evidence of disease was observed in 5 patients with available follow-up (range 12-124 months).Microscopically, all neoplasms were composed of variably sized, focally closed packed, or interconnecting nodules constituted mostly of cuticular cells. Small poroid cells were a focal feature in 5 tumors, whereas in the remaining 2 cases, poroid cells with conspicuous but still in minority. Five neoplasms were somewhat asymmetric, with irregular outlines. Ductal differentiation and intracytoplasmic vacuoles were seen in 6 tumors. Other features variably encountered were conspicuous intranuclear pseudoinclusions, cystic change, occasional multinucleated cells, increased mitoses, and stromal desmoplasia. Four of the 5 tumors analyzed with next-generation sequencing yielded YAP1::NUTM1 fusions. In addition, various mutations, mostly of unknown significance were identified in one neoplasm.

Atypical Non-neoplastic Changes in Anogenital Mammary-like Glands Accompanying Invasive Squamous Cell Carcinoma.

Long regarded as ectopic or supernumerary breast tissue, anogenital mammary-like glands (AGMLG) are now considered a normal constituent of the anogenital area. AGMLG are presumed to be the origin for various benign and malignant lesions. Changes in AGMLG compatible with usual ductal hyperplasia and atypical ductal hyperplasia considered as precursor lesions and its presence in specimens can be explained by their role in the pathogenesis of primary extramammary Paget disease. In this report, we presented four cases of invasive squamous cell carcinoma accompanied by non-neoplastic atypical changes in ductal portions of AGMLG compatible with atypical ductal hyperplasia in breast adjacent to the carcinoma. This is a reactive phenomenon similar to that seen in apocrine/eccrine glands adjacent to squamous cell carcinoma. In a limited biopsy specimen, these areas should not be mistaken for adenocarcinoma.

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.

Trichoblastoma: A Consecutive Series of 349 Sporadic Cases Analyzed by Ackerman Subtypes.

ABSTRACT: Trichoblastoma (TB) is a benign biphasic follicular neoplasm with differentiation toward the germinative cells and a specific follicular mesenchyme. We subtyped 349 sporadic TB according to a classification proposed by Ackerman. Two hundred forty-six (246/349, 70.5%) neoplasms were comprised of mixed subtypes. TB composed exclusively of a single pattern was less common (103/349, 29.5%). The most common pure subtype was cribriform TB followed by small nodular TB. Twelve cases (12/349, 3.4%) had unique features and are reported herein as novel histopathologic subtypes of the neoplasm.

Sebaceous Tumors of the Skin: A Study of 145 Lesions From 136 Patients Correlating Pathologic Features and DNA Mismatch Repair Staining Pattern.

ABSTRACT: Sebaceous neoplasms occur sporadically or in the setting of Muir-Torre syndrome. The data regarding the correlation of pathologic features and DNA mismatch repair (MMR) staining pattern in sebaceous tumors of the skin are very scanty and based on relatively small series of patients. The goal of this study was to correlate MMR staining pattern with selected morphological features in a series of 145 sebaceous neoplasms (sebaceous adenoma, sebaceoma, and extraocular sebaceous carcinoma) from 136 patients. Cystic change, intratumoral mucin deposits, squamous metaplasia in the absence of keratoacanthoma-like changes, ulceration, intratumoral and peritumoral lymphocytes (in cases without epidermal ulceration), and intertumoral heterogeneity proved to be significantly associated with MMR deficiency. Identification of any of these changes, alone or in combination, should prompt further investigation of the patient to exclude Muir-Torre Syndrome. Our study also confirms the previously published observation that the diagnosis and tumor location are significantly associated with MMR deficiency.

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.

Study of Selected BRCA1, BRCA2, and PIK3CA Mutations in Benign and Malignant Lesions of Anogenital Mammary-Like Glands.

Anogenital mammary-like glands (AGMLGs) are nowadays considered a normal component of the anogenital area. Lesions involving AGMLGs are histopathologically very similar to their mammary counterparts, but the information on molecular biological mechanisms in these vulvar/perianal tumors is scarce. Mutations in the PI3K-AKT cascade have been found in hidradenoma papilliferum. The authors studied selected BRCA1, BRCA2, and PIK3CA mutations in series of benign and malignant neoplasms thought to be associated with AGMLGs, including 9 cases of primary extramammary Paget disease, 3 different cases of mammary-type carcinoma (adenoid cystic like, tubulolobular, and invasive ductal like), and 5 cases of hidradenoma papilliferum. No BRCA mutation was detected, whereas 3 neoplasms yielded PIK3CA mutation, including extramammary Paget disease, mammary-type invasive ductal carcinoma, and tubulolobular carcinoma. Our study expands the spectrum of lesions of AGMLGs harboring mutations in genes encoding the PI3K-AKT cascade. Further studies of the whole BRCA1 and BRCA2 genes using a larger cohort are needed to clarify their role in the pathogenesis of AGMLG lesions.

An Immunohistochemical Study of Anogenital Mammary-Like Glands.

Although the normal histology of anogenital mammary-like glands (AGMLG) has been studied, no systemic investigation has been performed on the immunoprofile of these structures. We studied intact AGMLG with a broad panel of antibodies. The immunoprofile of AGMLG is similar to that of a normal breast tissue, and there are similarities to eccrine glands and coils about cytokeratin expression. Our immunohistochemical data may contribute to understanding of the pathogenesis of lesions arising from AGMLG.

Anogenital Mammary-Like Glands: A Study of Their Normal Histology With Emphasis on Glandular Depth, Presence of Columnar Epithelial Cells, and Distribution of Elastic Fibers.

The normal histology of anogenital mammary-like glands (AGMLG) has been studied previously, but some aspects, including glandular depth, presence of columnar epithelium resembling columnar cell change/hyperplasia as defined in mammary pathology, and distribution of elastic fibers, have not been previously investigated. To address these issues, we studied 148 AGMLG identified in 133 paraffin blocks sampled from 64 vulvar wide excision or vulvectomy specimens (64 patients, various indications for surgery). The depth of AGMLG ranged from 0.64 to 3.9 mm. Epithelial columnar cell change was noted in 33.1% of all AGMLG, whereas columnar cell hyperplasia was detected in 10.1%. Occasionally, combinations of cuboidal epithelium and columnar cell change were seen within 1 histological section. Of 22 specimens stained for elastic fibers, in only 6 (27.3%) cases were elastic fibers found around glands. Periductal elastic fibers were demonstrated around 3 of the only 5 ducts, which were available for analysis in slides stained for elastic fibers. The depth of AGMLG should be taken into account when planning topical and surgical therapies for lesions derived or evolving from AGMLG. Alterations identical to columnar cell change may represent a normal variation of AGMLG.

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.

Melanocytic Hyperplasia in the Epidermis Overlying Trichoblastomas in 100 Randomly Selected Cases.

One hundred cases of trichoblastomas (large nodular, small nodular, cribriform, lymphadenoma, and columnar) were randomly selected and studied for the presence of melanocytic hyperplasia in the epidermis overlying the tumors, which was defined as foci of increased melanocytes in the basal layer of the epidermis (more than 1 per 4 basal keratinocytes). Focal melanocytic hyperplasia was detected in a total of 22 cases of trichoblastoma (22%), and this phenomenon was most frequently seen in columnar trichoblastoma (7 cases), followed by large nodular trichoblastoma (5 cases). The mechanism of epidermal melanocytic hyperplasia overlying trichoblastoma is unclear. Ultraviolet may be a contributing factor, as focal melanocytic hyperplasia was also detected in one-third of cases in the epidermis overlying uninvolved skin, usually associated with solar elastosis. This is further corroborated by the occurrence of the lesions predominantly on the face. Melanocytic hyperplasia overlying trichoblastoma appears to have no impact on the clinical appearance of the lesion and is recognized only microscopically. In an adequate biopsy specimen containing at least part of trichoblastoma, it should not cause any diagnostic problems.

Bilateral Gigantomastia, Multiple Synchronous Nodular Pseudoangiomatous Stromal Hyperplasia Involving Breast and Bilateral Axillary Accessory Breast Tissue, and Perianal Mammary-Type Hamartoma of Anogenital Mammary-Like Glands: A Case Report.

Mammary-type fibroepithelial lesions involving ectopic breast and anogenital region are rare and usually coexist with normal orthotopic breast. We present what we believe to be a unique case of synchronous bilateral gestational gigantomastia resembling fibrous mastopathy, synchronous rapidly growing pregnancy-associated nodular pseudoangiomatous stromal hyperplasia involving right breast and bilateral axillary ectopic breast tissue, and metachronous perianal mammary-type hamartoma involving anogenital mammary-like glands occurring in a 34-year-old patient with facioscapulohumeral muscular dystrophy. Also, we review the literature concerning these lesions.

Syringomatous Structures in Extramammary Paget Disease: A Potential Diagnostic Pitfall.

Primary extramammary Paget disease (EMPD) is a form of intraepithelial adenocarcinoma. Different morphological changes may accompany EMPD, including the presence of syringoma-like structures. The authors report 10 cases of EMPD, all of which manifested syringoma-like structures within the dermis both in areas involved by the carcinoma and beyond, including at the margins of the excisions. All patients were women, whose ages ranged from 49 to 93 years (median 75 years). The possible pathogenesis of the syringoma-like lesions is discussed. Awareness of these structures in vulvectomy specimens for EMPD is important to prevent misinterpretation of the syringoma-like lesions as an invasive component of the EMPD.

Syringocystadenocarcinoma Papilliferum In Situ-Like Changes in Extramammary Paget Disease: A Report of 11 Cases.

The authors report 11 cases of extramammary Paget disease (EMPD), all of which also demonstrated a combination of histological changes highly reminiscent of syringocystadenocarcinoma papilliferum in situ. In addition to the classical features of EMPD, characterized by the intraepidermal spread of individually dispersed neoplastic cells with ample cytoplasm, many of which contained mucin, there were areas of acanthosis with the substitution of spinous layer keratinocytes by neoplastic cells, whereas the native basal cell layer was intact. In addition to acanthosis (and sometimes papillomatosis), the dermal papillae showed a prominent infiltrate of plasma cells, completing the resemblance to syringocystadenocarcinoma papilliferum in situ; this similarity was further enhanced in 2 cases, which showed conspicuous gland formation. One additional case showed multifocal dermal proliferations compatible with eccrine syringofibroadenoma (syringofibroadenomatous hyperplasia). The changes described herein seem to be relatively rare in EMPD, and they can represent a diagnostic pitfall, as evidenced by 2 cases that were originally misinterpreted as syringocystadenocarcinoma papilliferum in situ. Clinically, these microscopic changes sometimes corresponded to nodular lesions, which were specifically noted to have a papillated erosive surface.

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

Hidradenoma papilliferum (HP), also known as papillary hidradenoma, is the most common benign lesion of the female anogenital area derived from anogenital mammary-like glands (AGMLG). HP can be viewed conceptually as the cutaneous counterpart of mammary intraductal papilloma. The authors have studied 264 cases of HP, detailing various changes in the tumor and adjacent AGMLG, with emphasis on mammary-type alterations. In many HP, the authors noticed changes typical for benign breast lesions, such as sclerosing adenosis-like changes, usual, and atypical ductal hyperplasia. Almost in a third of cases, remnants of AGMLG adjacent to the lesion were evident, manifesting columnar changes reminiscent of those seen in breast lesions. This study shows that the histopathological changes in HP run a broad spectrum comparable with that in the mammary counterpart and benign breast disease.

Depth and Patterns of Adnexal Involvement in Primary Extramammary (Anogenital) Paget Disease: A Study of 178 Lesions From 146 Patients.

Extramammary Paget disease (EMPD) is a rare neoplasm usually presenting in the anogenital area, most commonly in the vulva. Adnexal involvement in primary EMPD is a very common feature and serves as a pathway for carcinoma to spread into deeper tissue. The depth of carcinomatous spread along the appendages and the patterns of adnexal involvement were studied in 178 lesions from 146 patients with primary EMPD. Hair follicles and eccrine ducts were the adnexa most commonly affected by carcinoma cells. The maximal depth of involvement was 3.6 mm in this series. When planning topical therapy or developing novel local treatment modalities for EMPD, this potential for significant deep spread along adnexa should be taken into account.

A composite neoplastic lesion of the vulva with mixed features of fibroadenoma and hidradenoma papilliferum combined with pseudoangiomatous stromal hyperplasia containing multinucleated giant cells.

Anogenital mammary-like glands (AGMLG) are nowadays considered a normal component of the anogenital area. Lesions affecting AGMLG are similar to those seen in breast. We present a case of a complex neoplastic lesion of the AGMLG with mixed features of fibroadenoma and hidradenoma papilliferum combined with pseudoangiomatous stromal hyperplasia. Multinucleated cells were detected in the pseudoangiomatous stromal hyperplasia areas as seen in some patients with neurofibromatosis type 1. The neoplasm is similar to rare mammary composite neoplasms that feature simultaneously patterns of a fibroepithelial neoplasms and intraductal papilloma.

Pigmented squamous intraepithelial neoplasia of the anogenital area: a histopathological and immunohistochemical study of 64 specimens from 45 patients exploring the mechanisms of pigmentation.

Pigmented lesions in the anogenital area encompass a wide variety of disorders including squamous intraepithelial neoplasia. The authors sought to explore the mechanism(s) underlying clinically pigmented squamous intraepithelial neoplasia in the anogenital area. A light-microscopic and immunohistochemical study of 64 lesional specimens from 45 patients (32 women, 13 men; age range, 23-73 years) with pigmented lesions in the anogenital area was performed. Histopathologically, 63 (98%) specimens showed melanin incontinence into the superficial dermis beneath the dysplastic epithelium. A focal or total loss of basilar hyperpigmentation was detected in 30 (48%) and 13 (20%) of lesions, respectively. In 17 (27%) cases, absence of basal layer hyperpigmentation was accompanied by a subepithelial lichenoid infiltrate. Melanin within the upper part of dysplastic areas were seen in 63 cases (98%), whereas dendritic melanocytes colonization, mild in all but 1 specimen case, was observed in 53 (83%) cases. All cases proved to be the usual type of squamous intraepithelial neoplasia; no single case of the simplex (differentiated) variant was present. The main mechanisms of pigmented squamous intraepithelial neoplasia of the anogenital area include melanin incontinence and occurrence of melanin in dysplastic keratinocytes. Colonization of the dysplastic epithelium by dendritic melanocytes seems to contribute, but it is rarely a prominent feature.

A tumoriform lesion of the vulva with features of mammary-type fibrocystic disease.

: Fibrocystic disease is a common benign lesion of the breast. Variably sized cysts, apocrine metaplasia, fibrosis, calcification, chronic inflammation, and epithelial hyperplasia are the basic morphological changes seen in mammary fibrocystic disease. We report a rare tumoriform lesion of the vulva with features of fibrocystic disease, which seems to be the first description of this condition in the vulva. The pertinent literature is discussed. The reported lesion further demonstrates the analogy between tumors of anogenital mammary-like glands and mammary neoplasms.

Multilocular mesothelial proliferation involving the skin of the umbilicus.

Multilocular mesothelial proliferation (MMP) is a rare lesion that mainly arises from the peritoneal mesothelium. Most often, it occurs in women of reproductive age, with a history of abdominal surgery, endometriosis, or pelvic inflammatory disease. We describe an unusual case of a 73-year-old woman affected by a large MMP, which involved the skin and presented clinically as a cutaneous mass. To the best of our knowledge, MMP involving the umbilicus has never been reported in a peer-reviewed literature.