Poroid Hidradenoma: A Rare Finger Lesion.

Poroid hidradenomas are uncommon tumors originating from eccrine sweat glands, often presenting as dermal nodules predominantly composed of cuticular and poroid cell types. They belong to the broader category of poroid neoplasms, which include hidroacanthoma simplex, dermal duct tumor, and eccrine poroma. Despite their rarity, poroid hidradenomas require accurate diagnosis and appropriate management due to potential overlaps in their histological features with other adnexal tumors, including digital papillary adenocarcinoma. We report a case of a 56-year-old female presenting with a nodular lesion on the palmar aspect of her right middle finger, which was excised under local anesthesia. Histopathological examination confirmed the diagnosis of poroid hidradenoma, highlighting the importance of maintaining a high clinical suspicion and precise histological evaluation in managing such an uncommon dermatological condition of the finger.

Ultrasonic features of hidradenoma papilliferum: An unexpected mass in the vulvar.

Hidradenoma papilliferum is a rare superficial mass with distinct ultrasonic features. It originates from mammary structures and is commonly observed in the anogenital region of women. We report a hidradenoma papilliferum with clear ultrasound images which have never be described before.

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.

Case report: thigh hidradenoma masquerading as lipoma.

Hidradenomas are benign adnexal neoplasms, which were recently been subdivided into two groups: eccrine differentiation (poroid hidradenomas) or apocrine differentiation (clear cell hidradenomas) with the latter being rarer. These types of tumors have been associated with recurrence and malignant transformation; however, recurrence and malignancy are considered very rare. We present a case report of a 35-year-old male who presented with two lumps, clinically representing simple lipomas but one of them turned to be a hidradenoma. A 35-year-old gentleman not known to have any medical illnesses and surgically free, presented to our general surgery clinic complaining of two slow-growing (over 3 years) painless lumps, one in the right upper thigh and the other one in the left shoulder. The patient denied any previous history of trauma or infection nor any history of discharge or overlying skin changes, and there were no clinical features that might suggest the presence of malignancy. Upon examination, both lumps were firm, freely mobile, non-tender, intact overlying skin, with no skin changes, and no regional lymphadenopathy. Prior to excision, our preliminary impression was lipoma for both masses. Surgical excision was carried out with clear margins; each mass was labeled separately, and specimens were sent for histopathology. Histopathological diagnosis of the left shoulder mass was consistent with lipoma; however, the right upper thigh mass turned to be a hidradenoma. Hidradenomas are uncommon benign neoplasms with varied types. Recurrence and transformation into malignancy have been reported in some cases. Complete surgical excision with negative margins and further follow-up with the patient are crucial to prevent such consequences. Clinical diagnosis can be difficult; however, the management is the same with surgical removal as it will give us the definitive diagnosis with the pathology report.

Hidradenoma of Pinna -Report of a Rare Case at a Rare Site.

There are various reports of hidradenoma of cartilaginous part of external auricular canal (ear), but the documented evidence of occurrence of hidradenoma of pinna is seldom available in world literature, hence we report one such case. The patient was a 45-year female with a lump in the region of the posterior aspect of the pinna of the right ear for the past 6 months. No history of pain except for serous discharge from the lump. FNAC of the lump showed histological feature of hidradenoma. Wide surgical excision of the lump was done under local anaesthesia and sent for histopathological examination. HPE confirmed the diagnosis of Hidradenoma. She is on follow up, till date no sign of recurrence.

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.

A Large Mass over the Foot due to the Coexistence of an Eccrine Poroma and a Poroid Hidradenoma: A Case Report.

Eccrine poroma and poroid hidradenoma are uncommon benign poroid neoplasms derived from eccrine sweat glands. There are four types of poroid neoplasms according to the position within the skin layer: hidroacanthoma simplex, eccrine poroma, dermal duct tumor, and poroid hidradenoma. Poroid neoplasms usually arise as slow-growing solitary lesions and can present different clinical presentations, such as a foot mass, an ulceration lesion, a solid cyst, a bleeding lesion or suspected melanoma. Extremities are the most common sites, especially hands and feet. However, the coexistence of these two tumors in a single lesion is extremely rare. Surgical excision represents the main treatment and can be curative, preventing malignant changes and recurrence. We describe a rare solitary tumor over the foot with clinical and histopathological features of an association of an eccrine poroma and a poroid hidradenoma that was surgically treated with no recurrence at the midterm follow-up. Level of Evidence IV, Case Report.

Ancillary immunohistochemical and molecular testing in the classification of cutaneous sweat gland/duct neoplasms: A validation study with emphasis on histomorphologic correlation and pathological diagnosis.

Sweat gland neoplasms represent a challenging area of dermatopathology, as they are relatively uncommon and often histopathologically complex. Recent studies have uncovered distinct immunohistochemical and molecular profiles in several sweat gland neoplasms, including digital papillary adenocarcinoma (DPA), papillary eccrine adenoma/tubular apocrine adenoma (PEA/TAA), poroid family tumors (PFT)/porocarcinoma, and clear cell hidradenoma (CCH)/clear cell hidradenocarcinoma (CCHCa). To further evaluate the diagnostic utility of ancillary studies in various sweat gland neoplasms, we performed an independent validation study in a cohort of patients with acral and non-acral tumors (9 DPA, 8 PEA/TAA, 13 PFT, 5 porocarcinoma, 23 CCH, 7 CCHCa, 6 sweat gland carcinoma not otherwise specified). p63 immunohistochemistry (IHC) demonstrated a myoepithelial pattern in 8/8 DPA and 4 of 4 tested PEA/TAA cases, and showed a ductal pattern in all tested PFT/porocarcinoma and CCH/CCHCa cases (42/42). All PEA/TAA (8/8) cases were positive for BRAF V600E IHC. 5 of 12 tested PFT and 5/5 porocarcinoma cases showed either positive staining with NUT IHC or harbored YAP1::NUTM1 fusion gene by RNA sequencing. MAML2 fluorescence in situ hybridization (FISH) was positive in all CCH and CCHCa cases (23/23 and 7/7, respectively). Our results further support the usefulness of appropriate ancillary studies in precise classification of sweat gland tumors, which may be routinely applied in diagnostic pathology practice when morphologic evaluation is in doubt.

A Rare Case of Ectopic Hidradenoma Papilliferum of the External Auditory Canal.

Hidradenoma papilliferum (HP) is a benign adnexal tumor, commonly affecting the anogenital region of middle-aged women. Clinically, HP typically presents as a slow-growing, unilateral, well-circumscribed, smooth skin-colored cystic dermal nodule, usually growing less than 1 cm in size. Reports of ectopic HP are exceedingly rare but have been identified in areas containing modified apocrine gland structures, most commonly on the head and neck, and have included ceruminous glands of the external ear canal, the Moll glands of the eyelid, mammary glands of the breast, maxillofacial region and areas on the scalp. To the best of our knowledge, there is only one case of ectopic HP located on the external ear canal reported in English literature. We present a second case of draining ectopic HP located on the conchal bowl of the external ear canal.

Clear cell hidradenoma of the breast with MAML2 gene rearrangement.

Clear cell hidradenoma is a rare benign tumor of the breast, its origin and pathogenesis are controversial. We have experienced a case of breast clear cell hidradenoma with mastermind like transcriptional coactivator 2 (MAML2) gene rearrangement. The patient found a painless mass with a hard texture in the left breast areola without nipple discharge. Microscopically, the tumor was cystic and solid, locally arranged in a glandular structure, covered by single cuboidal cells; it was composed of clear cells, epidermoid cells, and basaloid cells; there were no necrosis or mitotic figures. Immunohistochemical staining showed that the tumor cells positively expressed low-molecular cytokeratin 7, low-molecular cytokeratins (Cam5.2), high-molecular cytokeratin 5/6, cytokeratin 14, CD117, and p63; and did not express calponin, and smooth muscle myosin heavy chain. The cuboidal cells were positive for SOX10 but negative for p63. Additionally, periodic acid-Schiff reaction showed purple-red granules in the tumor cytoplasm, but Alcian blue staining showed no blue mucus in the cytoplasm. The split signals of MAML2 gene were detected by fluorescence in situ hybridization. Subtle histological and immunophenotypical differences may help to distinguish breast clear cell hidradenoma from common breast tumors. Furthermore, the MAML2 gene rearrangement may be a molecular genetic characteristic of breast clear cell hidradenoma.

Vulvar Hidradenoma Papilliferum.

Aim: This study examines the clinical and pathological characteristics, immune profile, histological occurrence, diagnosis, and differential diagnosis of vulvar hidradenoma papilliferum. Methods: An analysis was conducted on clinical data, histological patterns, and immunohistochemical findings from 45 cases of vulvar hidradenoma papilliferum, and relevant published articles were reviewed. Simultaneously, high-risk HPV typing was performed on these 45 cases. Results: The 45 cases of vulvar hidradenoma papilliferum displayed tumor sizes ranging from 0.3 to 2.0 cm and were observed to be pink or red in appearance. Vacuolated cytoplasm, large abnormal nuclei, distinct nucleoli, and scattered eosinophilic luminal secretions were observed in the glands. Positive staining for CK7 and progesterone receptor (PR) with focal mammaglobin and GCDFP-15 expression was found through immunohistochemistry. CK20 staining was noted as negative. Conclusion: Hidradenoma papilliferum is a rare benign tumor that originates in secretory glands. The diagnosis of this condition is aided by gross and immunohistochemical results, and differentiation from other conditions is necessary.

Remote Possibility of Post Aural Swelling as Nodular Hidradenoma: A Case Report.

A 30-year-old female patient presented with swelling over the left post aural region of 6 months duration which gradually increased in size. Cutaneous examination: A solitary, non-tender, mobile swelling of variable consistency over the post aural region. Dermoscopic examination: Revealed white and red areas. Diagnosis of nodular hidradenoma was made by histopathological examination.

Recurrent Malignant Sweat Gland Tumor.

Malignant sweat gland tumors are very rare. Hidradenocarcinoma is an uncommon malignancy arising from the intradermal ductal epithelium of eccrine sweat glands, usually in the sun-exposed parts of the body. It usually arises de novo but may develop from a benign hidradenoma. The diagnosis of hidradenocarcinoma is clinically challenging as it presents with varied consistency and clinically mimics other skin lesions such as chronic sebaceous cysts or epidermoid cysts. Hidradenocarcinoma is a highly aggressive tumor with a tendency for regional and distant spread. It is difficult to treat hidradenocarcinoma as it has high rates of morbidity and mortality and a very high incidence of recurrence. Here, we report a rare case of a 45-year-old woman who presented with a recurrent lump over the left arm diagnosed as primary hidradenocarcinoma.

Giant Poroid Hidradenoma of the Forearm.

Poroid hidradenoma represents an uncommon and benign tumor originating from skin adnexa. It falls under the category of sweet duct neoplasms, along with poromas. It affects the elderly population most frequently. Typically, it emerges as a small, distinct, and painless lump beneath the skin's surface, often occurring on the head and neck regions. It is characterized by a low risk of malignant transformation. Accurate identification relies especially on histomorphological analysis considering the intricate resemblance it shares with other tumors originating from eccrine glands. Poroid hidradenoma has only recently been recognized, and only a limited number of cases have been reported in the medical literature. In this instance, we present an unusual occurrence of a giant poroid hidradenoma on the left forearm of an elderly patient.

A Large Mass over the Foot due to the Coexistence of an Eccrine Poroma and a Poroid Hidradenoma: A Case Report / Poroma écrino associado a um hidradenoma poroide devido a coexistência de uma grande massa sobre o pé: Relato de caso

Abstract Eccrine poroma and poroid hidradenoma are uncommon benign poroid neoplasms derived from eccrine sweat glands. There are four types of poroid neoplasms according to the position within the skin layer: hidroacanthoma simplex, eccrine poroma, dermal duct tumor, and poroid hidradenoma. Poroid neoplasms usually arise as slow-growing solitary lesions and can present different clinical presentations, such as a foot mass, an ulceration lesion, a solid cyst, a bleeding lesion or suspected melanoma. Extremities are the most common sites, especially hands and feet. However, the coexistence of these two tumors in a single lesion is extremely rare. Surgical excision represents the main treatment and can be curative, preventing malignant changes and recurrence. We describe a rare solitary tumor over the foot with clinical and histopathological features of an association of an eccrine poroma and a poroid hidradenoma that was surgically treated with no recurrence at the midterm follow-up. Level of EvidenceIV, Case Report.

Resumo O poroma écrino e o hidradenoma poroide são neoplasias poroides benignas raras, derivadas das glândulas sudoríparas écrinas. Existem quatro tipos de neoplasias poroides, conforme a posição na camada da pele, sendo denominadas hidroacantoma simples, poroma écrino, tumor do ducto dérmico e hidradenoma poroide. As neoplasias poroides geralmente surgem como uma lesão solitária, com crescimento lento, podendo apresentar diferentes apresentações clínicas, como massa sobre o pé, lesão ulcerada, cisto sólido, lesão hemorrágica ou suspeita de melanoma. As extremidades são os sítios mais comuns, especialmente as mãos e os pés. No entanto, a coexistência desses dois tumores em uma única lesão é extremamente rara. A excisão cirúrgica representa o principal tratamento, podendo ser curativa, prevenindo assim as alterações malignas e as recidivas. Descrevemos um raro tumor solitário no pé com características clínicas e histopatológicas de uma associação de poroma écrino e hidradenoma poroide tratado cirurgicamente sem recidiva no acompanhamento de médio prazo. Nível de EvidênciaIV, Relato de Caso.

Poroid Hidradenoma: Case Report and Comprehensive Review of the Literature.

Poroid hidradenoma (PH) is a rare benign adnexal tumor of eccrine differentiation. It is the rarest of the four described variants of poroid neoplasms. PHs characteristically share a hybrid of the architectural features of the hidradenoma, namely, tumor cells are entirely intradermal with both solid and cystic components, and the cytologic characteristics of the poroid neoplasms, containing predominantly poroid and cuticular cells. Many published reports of PH since its original discovery in 1990 state that "very few" cases of PH can be found in the literature. Here, we have identified a total of 75 published accounts of PH, including the case presented here, as well as the associated patient demographics, lesion characteristics, treatment, and outcomes. We suggest that while uncommon, PH is likely not exceptionally rare and could be an underreported diagnosis.

An Unusual Presentation of Nodular Hidradenoma.

Benign adnexal neoplasms are quite a common occurrence in adults, especially in the head and neck region. They raise suspicion for malignancy if there are red flag signs like rapid increase in size, pain, ulceration or recurrence. We hereby report a case of a middle-aged gentleman who consulted our surgical OPD with right-sided neck swelling, which was initially thought to be a dermoid cyst; on further evaluation, found to be a dermal sweat gland tumour with features of nodular hidradenoma. The point that is of interest but coincidence to note is that this swelling was preceded by a minor trauma. Characterising these swellings using simple imaging and pathological investigation modalities is important to study their behavioural pattern and add the same to our existing database. This will also help the treating surgeons to keep in mind the possibility of occurrence of such histologies in soft tissue swellings when they present with uncommon clinical features, instead of brushing them aside as the common epidermal or dermoid cysts. Incidence of malignancy is almost nil in nodular hidradenoma, which when found, is attributed to poor surgical clearance; hence the prudence to operate with adequate clearance is extremely significant in preventing the transformation of a mole into a mountain.

Metastatic hidradenocarcinoma: a report of two rare cases.

BACKGROUND: Hidradenocarcinoma is a rare malignant sweat gland tumour, characterized by a slow but aggressive course, with high rates of local recurrence and metastasis. Due to its rarity, histological criteria and therapeutic guidelines are poorly defined, posing a major challenge for clinicians and pathologists. OBJECTIVES: To present two new cases of metastatic hidradenocarcinoma as well as a review of the literature. MATERIALS & METHODS: We describe two case studies and a review of the literature based on a search using the MEDLINE (PubMed) electronic database. RESULTS: The first patient was a 61-year-old woman with a perimamillary hidradenocarcinoma that arose from the malignant transformation of a benign childhood lesion and developed regional lymph node metastases after wide excision and adjuvant radiotherapy. The second patient was a 63-year-old man who developed cutaneous and renal metastases several years after the complete excision of a lumbar hidradenocarcinoma. As far as we can ascertain, kidney metastasis from hidradenocarcinoma has not previously been described. CONCLUSION: Most authors recommend wide excision as the treatment of choice for hidradenocarcinoma, however, optimal adjuvant therapy remains to be determined. Our cases add to the limited knowledge available, but high-quality studies to find new effective treatments are needed.

Hidradenocarcinoma of the Female Breast: A Surgical Approach to a Rare Skin Tumor.

Clear-cell hidradenocarcinomas are extremely uncommon sweat gland tumors with a predilection for the head and neck. In the limited number of articles reporting breast involvement, the primary focus concerns this entity's histological and immunohistochemical characteristics. Since hidradenocarcinomas of the breast have the potential to resemble a primary breast carcinoma closely, diagnosis may be challenging. Therefore, the authors report the first case of hidradenocarcinoma of the breast, which features its macroscopic morphology. In addition, to increase physicians' awareness of this rare neoplasm, the article also aims to detail its surgical approach.