Giant apocrine hidradenoma of the breast

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 papillary neoplasm of the breast with MAML2 gene rearrangement: Clear cell hidradenoma or low-grade mucoepidermoid carcinoma?

Clear cell hidradenoma (CCH) is an uncommon adnexal tumor usually arising from eccrine glands and commonly seen on the face and the upper extremities. CCH occurring in the breast is extremely rare. Herein we report a case of MAML2-rearranged CCH of breast with a papillary architecture closely mimicking intraductal papilloma, adenomyoepithelioma and low-grade mucoepidermoid carcinoma, thus representing a source of diagnostic confusion. An overview of salient histologic features and immunophenotypes to distinguish CCH and low-grade mucoepidermoid carcinoma is also integrated into the report.

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

Nodular hidradenoma is an uncommon cutaneous adnexal tumor arising from sweat glands. In the skin, it usually presents as a solitary dermal nodule; excision is curative in most cases. In rare instances, it may present as a breast mass and can mimic breast carcinoma clinically and radiologically, causing diagnostic dilemmas for the treating physician and pathologist. Herein, we discuss a case of nodular hidradenoma in a 20-year-old Hispanic woman as a rapidly growing mass in the breast that mimicked breast carcinoma. We discuss the rare presentation of this uncommon tumor and the differential diagnosis of this entity, as well as the results of our literature review on the topic.

MR Imaging of Mushroom-like Skin Adnexal Tumors in the Scalp: A Report of Two Cases

Few studies had been published regarding imaging findings of skin adnexal tumors. We experienced two giant cases of them with a characteristic mushroom-like growth pattern. MRI showed a circumscribed mushroom-like shaped mass extruding from the subcutaneous tissue with microcystic lesions. Although differentiation between benignancy and malignancy may be difficult by radiological examinations, MRI may be helpful to identify its origin and differentiate soft tissue tumors with skin adnexal tumors in having these imaging findings.

Clear Cell Hidradenoma: Characteristic Imaging Features on Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging

OBJECTIVES

The purpose of this study was to evaluate the imaging features of clear cell hidradenoma on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI).

METHODS

The radiologic and pathologic databases at 2 medical institutions were searched retrospectively from 2004 to 2016 to identify patients with a diagnosis of clear cell hidradenoma. Ultrasonographic, CT, and MRI features were described, and pathologic specimens were reviewed.

RESULTS

There were 5 female and 4 male patients. The mean patient age was 48.9 years (range, 28-70 years). Five patients underwent only US; 2 patients underwent only CT; 1 patient underwent both US and CT; and 1 patient underwent US and MRI. Most of the tumors were located primarily in the subcutaneous fat layer. The mean tumor size was 18.4 mm. On US, 6 masses had a heterogeneous echo texture, including an anechoic portion with protruding echogenic portions. Two masses had multiple septa in the anechoic portion. On color Doppler US, blood flow was both central and peripheral in 5 patients. All 3 cases seen on CT presented as a low-attenuation mass with an enhanced solid internal nodule. On MRI, the mass showed heterogeneous signal intensity on T2-weighted images and enhancement of the peripheral wall and internal solid component on contrast-enhanced T1-weighted images.

CONCLUSIONS

Clear cell hidradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, appears as a cystic mass with an internal solid nodule, and occasionally has multiple septa on US, CT, and MRI.

Malignant Clear Cell Hidradenoma of the Breast

A 58-year-old female had a mass in the right breast palpable beneath the areola. A mammogram revealed a 1.5-centimeter soft tissue density that was confirmed with a subsequent ultrasound. The patient underwent a core needle biopsy which was initially reported as a moderately differentiated invasive ductal carcinoma. Immunohistochemical analysis revealed negative staining for estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER2), mammaglobin, and gross cystic disease fluid protein 15 (GCDFP-15). A wide local excision of the mass was performed. The pathology report stated the tumor had an infiltrative growth pattern with a desmoplastic stromal response with enhanced epithelial atypia consistent with malignant transformation of a nodular clear cell hidradenoma. Clear cell hidradenoma is a very rare tumor originating from the sweat gland and has a propensity for the face and extremities. The malignant variant of this tumor is extremely rare and has been reported to originate from the breast in few cases. This case represents the difficulty in diagnosing this tumor along with the radiographic and histologic features that can distinguish this malignancy from other entities.

Combined Epithelial-Myoepithelial Lesions of the Breast

Epithelial-myoepithelial proliferations of the breast are a heterogeneous poorly defined group of lesions characterized morphologically by dual differentiation into ductal (luminal) and myoepithelial cells. They include neoplastic and non-neoplastic entities that have overlapping morphologic features that may give rise to diagnostic difficulty. Many of these entities are low grade or of uncertain malignant potential but the biology of some of these rare lesions remains to be elucidated. This article discusses the differential diagnosis of epithelial-myoepithelial lesions of the breast and highlights the morphologic features of some of these entities.

Giant clear cell hidradenoma of the knee

Hidradenomas, also referred to as nodular hidradenomas or clear cell hidradenomas (CCH), are benign cutaneous eccrine tumors usually 2-3 cm in dimension. Hidradenomas are relatively common; however, giant forms are rare. We report a case of an 8.0 x 6.0 x 3.0 cm clear cell hidradenoma of the left knee in a 43-year-old man. The tumor was mobile, located above the patellar tendon and was without bony involvement on imaging studies. Grossly, the resected tumor was unencapsulated and tan, with a solid and cystic cut surface showing papillary excrescences on the cyst wall. Microscopically, the tumor cells showed an infiltrative growth pattern at the periphery, however, the tumor cytology was bland and no necrosis or mitoses were identified. The overlying dermis contained hemosiderin pigment deposition and infiltration with eosinophils. Immunohistochemically, tumor cells were positive for cytokeratin, CAM5.2, p53, carcino-embryonic antigen (CEA) and epithelial membrane antigen (EMA), and negative for CD10 and Ki-67. The cytological features of hidradenomas can present diagnostic challenges, as other 'clear cell' tumors such as metastatic renal cell carcinoma should be considered. Immunohistochemical studies and differential diagnoses are discussed.

Cutaneous hidradenocarcinoma: a clinicopathological, immunohistochemical, and molecular biologic study of 14 cases, including Her2/neu gene expression/amplification, TP53 gene mutation analysis, and t(11;19) translocation

We present a series of 14 cases of cutaneous hidradenocarcinomas. The patients included 6 women and 8 men ranging in age at diagnosis from 34 to 93 years. All but 1 patient presented with a solitary nodule. There was no predilection site. One patient presented with multiple lesions representing metastatic nodules. Of 12 patients with available follow-up, 2 died of disease, whereas the remaining 10 patients were alive but 3 of them experienced a local recurrence in the course of the disease. Grossly, the tumors ranged in size from 1.2 to 6 cm. Microscopically, of the 14 primary tumors, 9 showed low-grade cytomorphology, whereas the remaining 5 neoplasms were high-grade lesions. The residuum of a hidradenoma was present in 5 of the 14 primaries. The mitotic rate was highly variable, ranging from 2 to 64 mitoses per 10 high-power field. The cellular composition of the tumors varied slightly, with clear cells, epidermoid cells, and transitional forms being present in each case. In 1 case, there was metaplastic transformation into sarcomatoid carcinoma. Glandular differentiation varied from case to case and appeared most commonly as simple round glands or as cells with intracytoplasmic lumens. Necrosis en masse was detected in 8 specimens. One specimen represented a reexcision and was unusual as it showed a well-demarcated intradermal proliferation of relatively bland clear cells accompanied by an overlying intraepidermal growth of clear cells resembling hidradenoacanthoma simplex. Despite the bland appearance, the tumor metastasized to a lymph node. Immunohistochemically, 5 of the 8 specimens studied for Her2/neu expression were negative, whereas 3 specimens from 2 cases yielded score +2, but all the 3 specimens with score 2+ subsequently proved negative for Her2/neu gene amplification by fluorescence in situ hybridization. Of 10 primaries studied, 4 tumors showed positive p53 immunoreaction in more than 25% of the cells comprising the malignant portion of the lesions, in 2 cases, a minority of the neoplastic cells (10%-20%) demonstrated nuclear staining, whereas the remaining 4 cases were negative. Of 9 specimens of hidradenocarcinoma studied for TP53 mutations, 2 harbored mutations, whereas the remaining 7 specimens showed the wild-type sequence. Of 11 specimens studied for translocation t(11;19), 2 cases harbored the translocation. It is concluded that cutaneous hidradenocarcinomas show some microscopic heterogeneity and comprise both low- and high-grade lesions that cytologically are similar to their benign counterpart, the hidradenoma. Within the spectrum of low-grade lesions, there seem to exist tumors almost indistinguishable from hidradenomas but still being capable of regional or distant metastasis. Similar to hidradenomas, hidradenocarcinomas show a t(11;19) translocation, but it is a significantly rarer event. Even rarer is the amplification of the Her2/neu gene. Of note is the relatively low frequency of TP53 mutations despite a high rate of p53 protein expression at the immunohistochemical level.

Benign hidradenoma: magnetic resonance and ultrasound features of two cases

Tumors of sweat gland origin are rare in the hand but should be considered in the differential diagnosis when certain imaging features are present. We present a case of nodular hidradenoma of the hand, with previously unreported magnetic resonance imaging features, and a further case in the thigh, both with ultrasound and histopathological correlation. The imaging literature of this tumor is reviewed, and its significance is discussed with respect to the current understanding of its malignant potential.