Atypical and malignant hidradenomas: a histological and immunohistochemical study

Abstract

The histological features of atypical hidradenoma are worrisome for increased risk of recurrence and possible malignant potential; however, earlier studies with immunohistochemistry or patient follow-up have not been reported. In addition, immunohistochemical analysis of hidradenocarcinoma exists in the literature mainly as case reports and as a single series of six cases. We compare the histological features and Ki-67, phosphorylated histone H3, epidermal growth factor receptor, and Her2/neu expression profiles of 15 atypical and 15 malignant hidradenomas with those of benign hidradenoma and metastasizing adnexal carcinomas. Infiltrative growth pattern, deep extension, necrosis, nuclear pleomorphism, and Z4 mitoses per 10 high-power fields are specific features of hidradenocarcinomas. Significant difference in mean Ki-67% was observed between benign and malignant hidradenomas (Po0.001), benign and metastasizing adnexal carcinomas (0.002), atypical and malignant hidradenomas (Po0.001), and between atypical hidradenomas and metastasizing adnexal carcinomas (0.002). Significant difference in mean phosphorylated histone H3% was observed between benign and malignant hidradenomas (Po0.001), benign and metastasizing adnexal carcinomas (0.003), atypical and malignant hidradenomas (Po0.001), and between atypical hidradenomas and metastasizing adnexal carcinomas (Po0.001). Mean epidermal growth factor receptor total score was significantly different in benign and atypical hidradenoma when compared with that in metastasizing adnexal carcinoma (P ¼ 0.014 and 0.019, respectively). Equivocal or 2 þ Her2/neu positivity was observed in one hidradenocarcinoma and in two metastasizing adnexal carcinomas. Receiver operating characteristic curve analysis for Ki-67 and phosphorylated histone H3% positivity reveals statistically significant criterion values of 411.425 and 40.7, respectively, for distinguishing malignant hidradenomas from atypical hidradenomas. Despite the presence of some worrisome histological features, the significantly different immunoprofile from the malignant counterpart suggests that atypical hidradenomas are likely to recur but are unlikely to metastasize. A tumor with Ki-67411% and/or phosphorylated histone H340.7% would likely be a malignant rather than an atypical hidradenoma. The infrequent Her2/neu overexpression in hidradenocarcinoma suggests its limited therapeutic role.

The Aesthetic and Oncological Challenges in the Management of an Atypical Nodular Hidradenoma of the Pinna

“…It has however been suggested by some authors that atypical hidradenomas have a significantly different immune-profile from its malignant counterpart showing a lower Ki-67 and PHH3 expression and a significantly different EGFR expression [3].…”

“…Rendering a diagnosis of hidradenocarcinoma can be challenging to the pathologists as some of these lesions do not possess the well-established criteria of malignancy [2]. Certain benign-appearing hidradenomas show focal atypical features and these tumors have been designated as atypical hidradenomas [3]. Herein we report a case of a 45-year-old woman with an atypical nodular hidradenoma of the pinna and discuss the aesthetic and the oncological issues pertaining to the reconstruction of the pinna.…”

Giant Poroid Submental Hidradenocarcinoma: Radiological Evaluation – Case Report

“…[3] These tumors require differentiation from metastatic and other malignancies like squamous cell and basal cell carcinomas. [4] Hemangiomas and lymphangiomas can also present in similar fashion. Recurrence rate is 10-70% and are more prone to Section: Ear, Nose & Throat metastasis.…”

Hidradenocarcinoma of scalp: a case report and review of literature

“…3 On immunohistochemistry, hidradenocarcinomas are variably positive for epidermal growth factor receptor (EGFR) in 80-85% of cases and are also positive for androgen receptor, oestrogen receptor, progesterone receptor. 10 Shu et al did immunehistochemistry for both of their hidradenocarcinoma patients and found that both cases were diffusely positive for EMA (epithelial membrane antigen) and Vimentin. 11 Surgery is the mainstay of treatment modality and postsurgical 5 year survival rate is found be less than 30%.…”