Hidrocystoma-like tumours with RET or ALK fusion: a study of four cases.

Hidrocystoma is thought to be a benign retention cyst of sweat ductal units. The lesion is usually located in the periorbital skin; however, lesions with similar histopathological features are rarely observed in extra-facial sites. Herein, we present four cases of hidrocystoma-like tumours in extra-facial skin sites that harboured a RET or ALK rearrangement. This study features a 67-year-old female with a 10 mm-sized digital tumour (Case 1), a 62-year-old male with an 8 mm-sized clavicular tumour (Case 2), a 61-year-old male with a 19 mm-sized digital tumour (Case 3), and an 11-year-old female with a 10 mm-size lower leg tumour (Case 4) as well as five control cases (Cases 5-9) of classical periorbital hidrocystoma. In Cases 1-4, multicystic tumours comprising a two-cell layer of inner cuboidal ductoglandular (p63- and SOX10+/-) and outer flat myoepithelial (p63+ and SOX10+) cells were observed. The inner ductoglandular tumour cells exhibited micropapillary projections and Roman bridging structures. No apparent atypical cells were observed. NCOA4::RET in Cases 1 and 3, CCDC6::RET in Case 2, and SLC12A2::ALK in Case 4 were revealed by next-generation sequencing or Sanger sequencing. In contrast, control cases of classical hidrocystoma (Cases 5-9) did not show intracystic proliferation, abundant cytoplasm, ALK immunoreactivity, or NCOA4::RET detection in the tumour cells. RET/ALK-rearranged hidrocystoma-like tumours are tumour entities that can be distinguished from classical hidrocystoma. This RET/ALK-rearranged neoplasm is benign and is frequently observed in the digits. Future studies will establish the concept, detailed clinicopathological characteristics, and genetic variations of hidrocystoma-like tumours.

Conjunctival Apocrine Hidrocystoma: A Case Report and Review of Literature.

PURPOSE: To describe the clinical features of a conjunctival apocrine hidrocystoma that developed 6 decades after a strabismus surgery and review existing literature on apocrine hidrocystomas of the conjunctiva and caruncle. METHODS: Case report and review of literature on conjunctival apocrine hidrocystomas. RESULTS: A 71-year-old man with a history of strabismus surgery as a child presented with a cystic lesion on the nasal conjunctiva and caruncle for 1 year. Excision of the lesion showed a unilocular cavity lined by a double layer of cells with the hallmark finding of apical decapitations, confirming a diagnosis of apocrine hidrocystoma. Seven additional cases of conjunctival and caruncular apocrine hidrocystomas were reviewed. All cases presented after 50 year of age. Most cases presented nasally or within the caruncle and had a pigmented appearance. No other reported cases had a history of trauma or surgery. All cases were treated with surgical excision without recurrence. CONCLUSIONS: History of strabismus surgery or conjunctival trauma may lead to ectopic deposition of apocrine glands that may contribute to the formation of an apocrine hidrocystoma.

Bilateral Eyelid Polyposis Due to Eccrine Hidrocystoma.

This case report discusses a diagnosis of eccrine hidrocystoma in a female patient aged 65 years who presented with bilateral, painless eyelid masses.

Apocrine Hidrocystoma of the Nail: A Unique Case.

ABSTRACT: Apocrine hidrocystomas are benign, cystic neoplastic lesions resulting from the apocrine secretory component of the sweat gland. They most commonly occur on the head and neck, with predilection to the periorbital area. Less frequent sites include the axilla, nipple, external auditory canal, foreskin, conjunctiva, lower lip, and fingers, among others. The authors report a unique case of a nail bed hidrocystoma in a 55-year-old woman, a site not previously described.

Adnexal neoplasms of the eye.

Adnexal neoplasms of the eyelid encompass a wide variety of benign and malignant tumors of sebaceous, follicular, and sweat gland origin. Due to the specialized structures of the eyelid, these neoplasms present differently when compared with those of other locations. Although most dermatologists and ophthalmologists are familiar with the commonly reported adnexal tumors of the eyelid, such as hidrocystoma, pilomatrixoma, and sebaceous carcinoma, many other adnexal neoplasms have been reported at this unique anatomic site. Accurate and timely identification of these neoplasms is essential, as alterations of eyelid anatomy and function can have a negative impact on eye health, vision, and quality of life. We review the clinical and histopathologic features of common and rare eyelid adnexal neoplasms and discuss proposed treatment options.

Apocrine cystadenoma: A long-standing apocrine hidrocystoma with an adenomatous proliferation.

BACKGROUND: Apocrine cystadenoma is a rare, benign adenomatous cystic neoplasm, the pathogenesis of which is not fully understood. We sought to characterize the clinical, dermatoscopic, and histopathologic features of apocrine cystadenoma and its relationship to hidrocystoma. METHODS: We retrospectively analyzed cases of apocrine cystadenoma and hidrocystoma retrieved from the dermatopathology laboratory information system. RESULTS: Of the 350 cases apocrine cystic lesions, 13 cases of apocrine cystadenomas met the inclusion criteria. The age ranged from 20 to 84 years with an average of 64 years. They were long-standing (duration 3-15 years), slow-growing, large tumors usually found on the scalp. Dermatoscopy accentuated translucent light to dark blue color and prominent vessels that were present more at the periphery. All lesions were multilocular with columnar to cuboidal lining and decapitation secretion. A large portion of the lesion consisted of a simple nonproliferative epithelial lining, identical to that observed in apocrine hidrocystomas, while the proliferative adenomatous component made up a smaller portion with two patterns: (1) tubular proliferation, which either protruded into the cystic cavity or expanded outward peripherally, or (2) papillary projections, which were multiple layers thick with fibrovascular core, sometimes accompanied by tubular proliferation. Immunohistochemical stains showed strong staining for p40 and a sparse number of cells stained for Ki-67 and p53. CONCLUSIONS: The long duration of the lesion and the large areas of simple apocrine epithelial lining suggest that apocrine cystadenomas arise from long-standing apocrine hidrocystomas. However, the retrospective nature of the study from a single institution is a limitation.

[Optical coherence tomography for the diagnosis and differentiation of cutaneous cysts: a case series]. / Diagnose und Differenzierung von kutanen Zysten mit optischer Kohärenztomographie: eine Fallserie.

Cutaneous cystic lesions (n = 35) were examined with optical coherence tomography. Cysts were visible as a hyporeflective roundish area with a clear margin; in some cases, the epidermis was thinned. Epidermal cysts, trichilemmal cysts, and hidrocystomas had a linear margin representing the epithelium of the cyst, whereas mucoid pseudocysts showed no linear margin. Trichilemmal and epidermal cysts presented with hyperreflective content that corresponds to keratin. By visualizing the margin and the content of the cyst, it was possible to differentiate between different types of cysts.

Pericanalicular eccrine hidrocystoma of the upper eyelid in a child.

A rare case of pericanalicular eccrine hidrocystoma of the upper eyelid is reported in a child who underwent surgical excision and canalicular repair with a successful outcome.

Apocrine Cystadenoma of the Eyelid, a Rare Neoplasm: Expanded Immunohistologic Profile.

An 83-year-old woman experienced the slow enlargement of a right lower eyelid mass. Histopathologic examination of the excised tissue showed a mucin-filled cystic tumor emanating from an apocrine bilayer that displayed bleb-like apocrine decapitation secretion. The outer flattened myoepithelial layer of the bilayer reacted with immunohistochemical stains for smooth muscle actin and calponin. In foci, the tumor exhibited a cribriform architecture with small pockets of mucin. Tumor cells were reactive for cytokeratin 7, Gross Cystic Disease Fluid Protein 15 (BRST-2), estrogen and progesterone receptors, androgen receptors, mammaglobin, epithelial membrane antigen, and GATA3. Ki67 showed a very low proliferation fraction. The lesion exemplifies the fourth instance of an eyelid apocrine cystadenoma in the literature.

Apocrine Papillary Hidrocystoma With Mucinous Metaplasia (Goblet Cell Type): A Case Report and Review of the Literature.

ABSTRACT: Mucinous metaplasia (goblet cell type) is exceptionally rare in the skin. This is the second case of apocrine papillary hidrocystoma with mucinous metaplasia (goblet cell type) and a review of the literature exploring the significance and frequency of mucinous metaplasia with goblet cells in nongenital skin. The patient is an elderly man who presented with a blue-pigmented nodule on the scalp that was clinically suggestive of an atypical nevus. Histologically, the lesion was composed of a simple cyst of cuboidal cells with decapitation secretion and mucinous metaplasia with goblet cells. Papillary formation was identified in the cysts. Most cases of cutaneous mucinous metaplasia have been reported on genital skin, usually after chronic inflammation of the area. This type of mucinous metaplasia is categorized as benign mucinous metaplasia of the genitalia (BMM) and is believed to be unrelated to apocrine glands owing to the different histologic features and absence of apocrine differentiation by immunohistochemistry. Mucinous metaplasia (goblet cell type) has been previously reported in benign adnexal tumors (eccrine acrospiroma/hidroadenoma, mixed tumor, and syringocystadenoma papilliferum) and in malignant tumors (apocrine hidradenocarcinoma and squamous cell carcinoma). To date, mucinous metaplasia has not been identified in the histologically normal apocrine glands.

Eccrine Cyst (Hidrocystoma) of the Inner Canthus: A Rare Entity With Immunohistologic Confirmation.

A small ruptured cyst was excised from the left inner canthus of a 68-year-old woman. Histopathology displayed a cyst lined by a double layer of cuboidal epithelium and filled with amorphous material. The lining cells were strongly positive for cytokeratins 5/6 and 14, with weak reactivity with cytokeratin 7. These findings were identical to those in a single previous report of an eccrine cyst of the eyelid, making this the second example of a bona fide eccrine hidrocystoma of the eyelid.

Median raphe cysts: A clinico-pathologic and immunohistochemical study of 52 cases.

BACKGROUND: Median raphe cysts (MRC) are epithelial-lined cystic lesions of the genital area that do not communicate with the urethra or the overlying epidermis. Immunohistochemically, MRC show positivity for cytokeratin (CK) 5-6, CK 7, carcinoembryonic antigen, p63 and uroplakin III (URO III). GATA3 and human milk fat globulin 1 (HMFG1) are immunohistochemical markers that have been not previously studied in MRC. METHODS: We conducted a study of 52 patients diagnosed with MRC in the Pathology Departments of eight hospitals between 1990 and 2016. The monoclonal antibodies used were CK5-6, CK7, CK20, URO III, p63, GATA3, and HMFG1. HMFG1 was studied in five cases of apocrine hidrocystomas and compared with five cases of MRC from our series. RESULTS: CK 5-6, CK7, and p63 expression showed strong positivity in the urothelial epithelium of 48 cases. CK20 was focally positive in areas of mucinous differentiation in three cases. GATA3 showed intense nuclear staining in 30 cases. HMFG1 was positive in three cases of MRC and in three cases of apocrine hidrocystoma. CONCLUSION: Positivity of GATA3 and CK7 in MRC supports the urothelial origin of these cysts. We found no differences in HMFG1 expression between MRC and apocrine hidrocystomas.

Apocrine Hidrocystoma of the Parotid Gland.

Apocrine hidrocystoma is a cystic tumor originating from apocrine sweat glands. It is predominantly located in the eyelid margins. Here, we report a case of apocrine hidrocystoma of the parotid gland in a 19-year-old man who was referred to our outpatient clinic with a 5-year history of a gradual swelling in the left parotid region. The patient underwent left superficial parotidectomy. Histological examination confirmed the diagnosis of apocrine hidrocystoma. The case is original by the tumor's location: to the best of our knowledge, this could be the first case in English and French literature reporting an apocrine hidrocystoma affecting the parotid gland. The purpose of this article is to report our case and discuss its clinical and anatomopathological features as well as its differential diagnoses.

Episcleral Apocrine Hidrocystoma Following Strabismus Surgery.

Apocrine hidrocystomas are benign cystic tumors derived from apocrine sweat glands; they are most commonly located in the skin of the head and neck regions. Ophthalmic occurrences typically appear at the lash line and canthi of the eyelid, although rare instances have been described in the conjunctiva, caruncle, and orbit. The authors illustrate an exceptional instance of a mobile episcleral cyst in a 12-year-old girl that developed about 2 years following strabismus surgery. The cyst was located anterior to the insertion of the left medial rectus and was excised in response to the patient's complaints of irritation. Histopathology of the excised specimen displayed an empty cyst lined by a double layer of cuboidal epithelium with the inner layer exhibiting apical decapitation secretion. Confirmatory immunohistochemistry demonstrated reactivity of both layers with CK7 and the outer myoepithelial layer with D2-40. Postoperative and traumatic cysts formed after interruption of the bulbar conjunctiva are usually conjunctival cysts lined by stratified squamous nonkeratinizing epithelium.

Apocrine Hidrocystoma with IgG4 Plasma Cell Infiltration Presenting as Recurrent Chalazion: A Case Report.

Apocrine hidrocystomas are benign cystic tumors resulting from apocrine sweat glands' proliferation. They typically present as solitary, slow-growing nodules at the head and neck, especially in the periorbital cutaneous region. We present a case of periorbital apocrine hidrocystoma in a 22-year-old woman that was treated as chalazion previously. Besides the hallmark histopathological findings of apocrine hidrocystoma, IgG4 plasma cell infiltration of the cystic wall was also found. The ratio of IgG4-to-IgG-positive plasma cells was high, whereas serum IgG4 was within the standard limit. This is, to date, the only probable IgG4-related ophthalmic disease associated with apocrine hidrocystoma.