Introduction:

The FNA of the tumor revealed material compatible with cystic contents, negative for malignant cells.

After the tests, it was decided to perform resection of the tumor under local anesthesia and sedation using a submandibular approach and layered dissection. Layered closure was achieved with subcutaneous absorbable sutures and non-absorbable skin sutures.

The sample was sent for histological study, the report of which was: deep dermal cystic formation with a hyperplastic, solid, papillary epithelial lining, composed of small and medium-sized eosinophilic cells, without atypia, and an eccrine phenotype. Focally, a deposit of amorphous eosinophilic material with cellular debris was identified within the lesion. The conclusion was: right submandibular mass consistent with eccrine hidradenoma.

Results.

The patient made a good recovery. He had no bleeding or infection episodes during the postoperative period. He has been followed up with no signs of local or distant recurrence.

Discussion.

Eccrine hidradenoma, also known as nodular hidradenoma, clear cell myoepithelioma, solid cystic hidradenoma, clear cell eccrine sweat gland adenoma, or eccrine acrospiroma (1) is a rare tumor belonging to the family of cutaneous appendage tumors. It is a benign, solitary, asymptomatic, skin-colored tumor arising from the intraepidermal and dermal portion of the internal sweat duct, located primarily in the dermis.

The review by Hernández-Pérez and Cestoni-Parducci showed a mean age of onset of around 37.2 years, with the most common site of presentation being the scalp. The male/female ratio was 1:1.7 (2).

The diagnosis of this type of tumor is histological, consisting of lobulated masses located in the dermis that can extend into the subcutaneous tissue (3). Furthermore, it is usually well-circumscribed and encapsulated, with cystic foci and tubular lumens containing homogeneous eosinophilic material, as seen in our case. The wide variety of cutaneous appendage tumors makes immunohistochemistry essential in many cases to differentiate tumors with ambiguous histopathological characteristics. In the case of eccrine hidradenoma, malignant transformation is rarely observed (4); however, a thorough differential diagnosis is important, as it can be confused with other entities such as lipoma, squamous or basal cell epithelioma, mucous cyst, and so on.

Furthermore, cutaneous appendage tumors may be associated with genetic syndromes such as Birt-Hogg-Dubé, Cowden, and Muir-Torre syndromes, and it is important to rule them out in the case of multiple tumors.

The treatment of this tumor is always surgical, referring the specimen to pathological anatomy for confirmation diagnosis (5).

The interest of this clinical case lies in the rarity of this type of tumor and the limited literature available regarding its diagnosis and management.

Conflicts of Interest.

The authors explicitly declare that there are no conflicts of interest related to the preparation, development, or publication of this article.