Lymph node location of a clear cell hidradenoma: report of a patient and review of literature

Case report: High-grade hidradenocarcinoma of the chest wall with insights from 18F-FDG PET/CT imaging and a review of the literature

Hidradenocarcinoma (HAC) is a rare neoplasm that typically occurs in the head and neck region but seldom affects the chest wall. Histopathology and immunohistochemistry remain essential for diagnosing HAC, although their clinical utility in determining metastasis can be limited. Given the pathological rarity and histopathological heterogeneity of HAC, we report a case demonstrating the utility of positron emission tomography/computed tomography (PET/CT) combined with immunohistochemical examination for the accurate diagnosis and staging of HAC. An 84-year-old woman presented to our hospital with a right chest wall and axillary mass. A pathological examination was performed, which revealed a malignancy of epithelial origin. The immunohistochemical examination confirmed a high-grade hidradenocarcinoma. Subsequently, PET/CT examination showed significant hypermetabolism in the right chest wall and its ipsilateral axillary and subclavian lymph nodes. Combined with pathological findings, these results confirmed metastatic hidradenocarcinoma, leading to a TNM classification of T2N3M (stage IV). A literature review revealed that HAC rarely occurs in the chest wall but tends to metastasize. However, the prognosis is favorable, especially with early diagnosis and surgical intervention. 18F-FDG PET/CT examination is a valuable staging tool in the comprehensive assessment of systemic tumor metastasis. Combining PET/CT with pathological examination enhances diagnostic and staging accuracy, enabling timely treatment and improving outcomes.

A rare case of hidradenocarcinoma with anaplastic and invasive features arising from a nodulocystic hidradenoma

A 91-year-old man presented with a cutaneous left abdominal mass. The mass was longstanding (over 5 years) and slow-growing. Examination revealed a violaceous, multinodular, and exophytic non-tender mass surrounded by patchy erythema. Excisional biopsy was performed and revealed a nodular and cystic dermal proliferation of predominately basaloid cells with focal duct formation, surrounded by prominent hyalinized stroma. The superficial portion of the mass was identified as a nodulocystic hidradenoma. Along the deep aspect and in association with the benign hidradenoma, sheets of markedly atypical epithelioid cells invaded the surrounding tissue, consistent with malignant transformation. Perineural and lymphovascular invasion were seen among areas with anaplastic features. This case supports that some hidradenocarcinoma originates from benign counterparts, and as such, ample sampling is required to definitively exclude a more sinister diagnosis. Diagnostic, prognostic, histopathological, and molecular characteristics, and current knowledge limitations are briefly discussed.

Ultrasound Features of Nodular Hidradenoma: A Case Series of 27 Patients

OBJECTIVE

The aim of this study was to systematically investigate the ultrasonographic features of nodular hidradenoma (NH).

METHODS

A retrospective analysis was used to systematically summarize the ultrasonographic data of 27 patients diagnosed with NH by surgical pathology, including 13 eccrine nodular hidradenomas (ENH) and 14 apocrine nodular hidradenomas (ANH).

RESULTS

All instances of NH presented as solitary, well-defined lesions that infiltrated the dermis and subcutaneous fat layer, characterized by a heterogeneous hypoechoic internal solid component on ultrasound imaging. Color Doppler ultrasound revealed blood flow signals of Grade 2 or higher within 74% (20/27) of the lesions. Solid + cystic (cystic >50%) NH (14/27, 51.4%) were typically large and predominantly had an oval shape (11/14, 78.5%). Their distinctive sonographic features included the presence of inner septa within the cystic area (8/14, 57.1%), "snow falling" sign (7/14, 50%), or "fluid-fluid level" sign (7/14, 50%). Solid + cystic (cystic ≤50%) NH exhibited a lobulated morphology in all instances (5/5, 100%). No inner septa, "snow falling" sign or "fluid-fluid level" sign was observed within the cystic regions. The solid NH (8/27, 29.7%) morphology predominantly featured lobulation (6 out of 8, 75%). Ultrasound analysis revealed distinct differences between ENH and ANH. ENH were more lobulated, while ANH were predominantly oval. ANH were mainly solid + cystic (cystic >50%), whereas ENH were mostly solid. Inner septa, "snow falling" sign, and "fluid-fluid level" sign frequencies were similar in both groups, correlating more with cystic-solid composition than pathological subtype.

CONCLUSIONS

Ultrasonographic features of lobulated morphology and the presence of inner septa, "snow falling" sign or "fluid-fluid level" sign in the cystic region provide strong support for the diagnosis of NH.

Cutaneous balloon-cell melanoma metastases to the axillary lymph node: Exploring cytomorphologic features and differential diagnoses on fine needle aspiration biopsy

Balloon cell melanoma (BCM) is an exceptionally uncommon histological variant, making up <1% of all malignant melanomas. Diagnosing balloon cell melanoma on cytological specimens can be challenging due to its scarcity and its similarity to other medical conditions. A comprehensive clinical assessment and histological analysis, coupled with immunohistochemical staining, play a crucial role in distinguishing balloon cell melanoma from various benign and malignant skin conditions. The differential diagnoses encompass spitz nevus, balloon cell nevus, clear cell sarcoma of tendons and aponeuroses (melanoma of soft tissues), metastatic clear cell renal cell carcinoma, sebaceous carcinoma, and benign adnexal tumours like clear cell hidradenoma.

Malignant melanoma encompasses a spectrum of histopathological subtypes, each with unique clinical and cytological characteristics. Notably, balloon‐cell melanoma (BCM) emerges as an exceptionally rare and diagnostically challenging variant. Marked by the presence of distinct balloon‐like, clear cytoplasmic vacuoles within melanoma cells, BCM stands apart from other melanoma subtypes. Despite its rarity, the distinctive cytological features of BCM make it a compelling subject of investigation, emphasizing the crucial role of Fine Needle Aspiration (FNA) cytology in ensuring accurate diagnosis and guiding subsequent management decisions.

Genetic and Immunohistochemical Profiling of Mammary Hidradenoma and Comparison to Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) is exceedingly rare in the breast, with <45 cases reported in the literature. Although estrogen receptor/progesterone receptor/human epidermal growth factor 2 triple-negative, MEC is characterized as a special subtype of breast carcinoma with significantly better prognosis than conventional basal-type tumors. Cutaneous hidradenoma (HA) is considered a benign adnexal neoplasm showing histomorphologic overlap with MEC. Rare cases of HA have also been reported in the breast, but these are relatively uncharacterized. In this study, we examined the clinicopathologic, immunohistochemical (IHC), and genetic features of 8 breast HAs, in comparison to 3 mammary MECs. All cases were positive for MAML2 break-apart fluorescence in situ hybridization. Eight cases demonstrated a CRTC1::MAML2 fusion, and one MEC harbored a CRTC3::MAML2 fusion; the latter is a novel finding in the breast. Mutational burden was very low, with only one HA exhibiting a MAP3K1 pathogenic alteration. By IHC, both MEC and HA demonstrated cell type-dependent expression of high- and low-molecular-weight keratins and p63, as well as negative to low-positive estrogen receptor and androgen receptor. Smooth muscle myosin and calponin highlighted an in situ component in the 3 cases of MEC; expression of these myoepithelial markers was negative in HAs. Additional distinguishing characteristics included the growth pattern and tumor architecture, the presence of glandular/luminal cells in HA, and overall higher IHC expression of SOX10, S100 protein, MUC4, and mammaglobin in MEC. Morphologic findings were also compared to a series of 27 cutaneous nonmammary HAs. Mucinous and glandular/luminal cells were identified in significantly more mammary HAs than nonmammary lesions. The findings provide insight into the pathogenesis of MAML2-rearranged neoplasms of the breast, underscore the overlapping genetic features of MEC and HA, and highlight similarities to their extramammary counterparts.

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.

Two distinct pathogenic pathways of digital papillary adenocarcinoma - BRAF mutation or low-risk HPV infection

Digital papillary adenocarcinoma (DPA) is a rare neoplasm that can exhibit local recurrence and distant metastasis. We present a series of eight cases of DPA showing two distinct clinical presentations, morphologies, immunophenotypes, and molecular features. Four cases were characterized by painless, slow-growing nodules located on the digits. The lesions were small, well-defined, and confined in the dermis. Histopathologically, these tumors were composed of glandular structures lined by cuboidal epithelium with luminal papillary infoldings. Only rare mitotic figures and minimal squamoid differentiation were present, and cellular necrosis was absent. All four cases were positive for the BRAF V600E immunohistochemistry but negative for p16, low-risk and high-risk HPV in situ hybridization (ISH). In contrast, the remaining four cases were characterized by painful, rapidly growing masses on the digits. These four lesions were located in the deep dermis and consisted of a solid, tightly packed papillary architecture lined by atypical epithelioid cells with inconspicuous nucleoli. Cellular necrosis, numerous mitotic figures, and prominent squamoid differentiation were seen. All cases were negative for the BRAF V600E IHC. However, they showed strong, patchy to diffuse reactivity for p16 and were positive for low-risk HPV ISH and negative for high-risk HPV ISH. Our findings suggest that the current classification of DPA encompasses tumors that show two discrete pathogenic pathways - BRAF mutation or low-risk HPV infection. DPAs with low-risk HPV infection exhibit aggressive clinical features, high-grade morphology, marked squamoid differentiation, and wild-type BRAF. DPAs with BRAF V600E have less aggressive clinical features, low-grade morphologic findings, mild to absent squamoid differentiation, and negative HPV infection.

Clinicopathological and genomic copy number variation analysis in nodular hidradenoma and hidradenocarcinoma with focus on prognostically important features

Nodular hidradenoma is a cutaneous adnexal tumor of sweat gland origin, characterized by its diverse but overlapping histomorphologic features with other skin tumors. In addition, distinction of benign hidradenoma and its malignant counterpart hidradenocarcinoma can be challenging, especially in prognostic prediction. We retrospectively reviewed pathological features of 29 cases, including benign nodular hidradenoma (n = 17) and hidradenocarcinoma (n = 12), with clinical follow-up ranging from 18 to 216 months. Genomic copy number variation (CNV) was studied in selected cases (n = 18) by single nucleotide polymorphism microarray. None of the benign hidradenomas (0/17) or low-grade hidradenocarcinomas (0/6) had recurrence or metastasis after complete excision, whereas all 6 high-grade hidradenocarcinomas (6/6) showed locally destructive disease, recurrence, or local metastases. In benign hidradenomas, CNV abnormality was absent in all clear cell hidradenomas (0/5) but was detected in a considerable portion of poroid hidradenoma (3/5), with number of abnormalities ranging 2, 4, and 9. In malignant cases, regardless of morphological classification, both low-grade hidradenocarcinomas demonstrated limited CNV abnormalities in 2 areas (2/2), whereas all high-grade hidradenocarcinomas contained 8 or more CNV abnormalities (6/6). No disease-associated death was recorded in the cohort except one case was lost to follow-up after the development of metastatic disease. Overall, the findings support that genomic CNV abnormalities may serve as a sensitive but less specific tool in detecting malignancy in these tumors, and potentially have a role in predicting clinical behavior particularly in the tumors of nonporoid morphology.

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Three Cases of Clear Cell Hidradenoma With "Benign" Lymph Node Involvement

ABSTRACT

The malignant counterpart of cutaneous clear cell hidradenoma (CCH), hidradenocarcinoma, is an aggressive neoplasm that may have a fatal outcome. However, some cases of benign looking CCH with isolated lymph node involvement and excellent prognosis have been described. "CCH-like neoplasm of uncertain malignant potential" or "atypical hidradenoma" have been proposed as designations for these lesions. We report 3 cases of CCH with lymph node involvement. Ages ranged from 29 to 51 years old. All cases involved the inguinal lymph nodes: 2 of them presented with an isolated lymph node lesion, and the third case had lymph node and cutaneous involvement following the resection of a previous cutaneous lesion. Imaging studies showed no systemic involvement. None of the lesions exhibited histopathologic features of malignancy. All neoplasms were well circumscribed, had cystic spaces, did not display atypia or necrosis, and had less than 4 mitoses per high power field. No recurrence has been observed at follow-up after resection in all cases. All published cases of CCH with lymph node involvement so far affected a single lymph node in the axillary or inguinal regions, lacked features of malignancy, and had excellent long-term prognosis. Some cases previously reported as hidradenocarcinoma probably fit into this category. Our series adds more evidence to this rare phenomenon of "benign metastasis." Aggressive treatment should be avoided in these cases, and a long-term follow-up is warranted.

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.

Malignant acrospiroma: a case report in the era of next generation sequencing

Background

Malignant acrospiroma is a rare tumor of the eccrine sweat glands accounting for around 6% of all malignant eccrine tumors. Typically, it presents as large ulcerated nodules, and diagnosis can be challenging as it has great overlap with its benign counterpart.

Case presentation

We herein report a case of acral malignant acrospiroma, initially treated with surgical excision and adjuvant radiotherapy. After metastatic disease was confirmed, subject received multiple lines of chemo- as well as targeted therapy. Genomic testing was also done using next generation sequencing.

Conclusion

To the best of our knowledge, this is the first case of acral malignant acrospiroma with reported next generation sequencing results.