Case Report and Literature Review of Nodular Hiradenoma, a Rare Adnexal Tumor That Mimics Breast Carcinoma, in a 20-Year-Old Woman

Apocrine hydroadenoma mimicking a Morton's neuroma: a rare differential diagnosis

A 62-year-old woman, with neuropathic pain and paresthesia in her right forefoot, showed a circumscribed soft tissue swelling on the sole between the second and third metatarsal. Ultrasound (US) imaging showed a well-defined lesion in the second intermetatarsal space, without vascularization sign at Power Doppler (PD). In the first hypothesis, these findings led to Morton's neuroma. Magnetic Resonance Imaging (MRI), demonstrated a dumbbell-shaped lesion between the II and the III metatarsal heads; it extended cranially to the subcutaneous fat of the dorsal slope. The MRI findings weren't compatible with a classic Morton's neuroma and were radiologically undetectable. The patient had a sub-total excisional biopsy. The anatomopathological features were specific to an apocrine hydroadenoma from an ectopic sweat gland. This rare pathology has not been previously described in the literature and it must be considered as a differential diagnosis due to the clinical presentation and the US appearance mimicking Morton's neuroma.

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.

Diagnostic Pitfalls in Breast Cancer Pathology With an Emphasis on Core Needle Biopsy Specimens

CONTEXT.—

Breast pathology has many mimics and diagnostic pitfalls. Evaluation of malignant breast lesions, particularly in the biopsy setting, can be especially challenging, with diagnostic errors having significant management implications.

OBJECTIVE.—

To discuss the pitfalls encountered when evaluating ductal carcinoma in situ and invasive breast carcinomas, providing histologic clues and guidance for appropriate use and interpretation of immunohistochemistry to aid in the correct diagnosis.

DATA SOURCES.—

Data were obtained from review of pertinent literature of ductal carcinoma in situ and invasive breast carcinomas and from the experience of the authors as practicing breast pathologists.

CONCLUSIONS.—

Awareness of the pitfalls in diagnosing breast cancers is important when creating a differential diagnosis for each breast lesion evaluated. This review will cover some of these scenarios to aid in the diagnostic process.

Clear Cell Hidradenoma of the Breast Diagnosed on a Core Needle Biopsy: A case report and review of the literature

Clear cell hidradenoma (CCH) is a tumour originating from the eccrine sweat glands. It usually presents in the limbs, axilla or trunk. CCH of the breast is rare and can present as a cystic lesion in the breast that can be easily misdiagnosed as malignancy. We report a 36-year-old female patient who presented at the Sultan Qaboos University Hospital Breast Clinic, Muscat, Oman, in 2018 with a lump in her left breast. Ultrasound examination reported a complex cystic lesion with a solid, vascular component. An ultrasound-guided core needle biopsy was suggestive of clear cell hidradenoma. Surgical excision was performed and histopathology confirmed the diagnosis of CCH of the breast. This is the first ever case of a diagnosis of CCH made using core needle biopsy. CCH can be challenging to diagnose; therefore, awareness of its histopathological and ultrasonographic features are essential to avoid misdiagnosis and over treatment.