Metastatic hidradenocarcinoma with demonstration of Her-2/neu gene amplification by fluorescence in situ hybridization: potential treatment implications

J Cutan Pathol. 2007 Jan;34(1):49-54. doi: 10.1111/j.1600-0560.2006.00570.x.


A 44-year-old man was referred for a right chest nodule of 3 months duration. A 'benign' nodule had been excised from this location 8 years prior. On examination, palpable nodes were noted in the right axilla. Radiographic studies were significant only for right axillary lymphadenopathy. Histologically, a nodular dermal proliferation composed of poorly differentiated epithelioid cells in nests and focally forming ducts with pseudopapillary architecture comprised the primary tumor. Features of a clear cell hidradenoma were noted focally. Immunohistochemical (IHC) analysis revealed reactivity for HMW cytokeratins, CK5 and CK7, p53, p63, CEA (focal), androgen receptor, EGFR, estrogen receptor (ER), MUC5AC, and strong/diffuse membranous staining for Her-2/neu. Negative stains included villin, TTF-1, CDX2, S-100 protein, vimentin, gross cystic disease fluid protein 15 (GCDFP-15), mammoglobulin, and MUC2. A wide local excision and axillary node dissection was performed. Metastatic tumor involved nine of 28 nodes. Interphase fluorescence in situ hybridization (FISH) demonstrated chromosomal amplification of the Her-2/neu locus within the tumor and a nodal metastasis. The patient has completed adjuvant and radiotherapy, including trastuzumab, and is asymptomatic. We believe this to be the first demonstration of Her-2/neu amplification in a malignant skin adnexal tumor. In analogy to breast carcinoma, these findings suggest the applicability of trastuzumab for patients with metastatic adnexal carcinomas demonstrating Her-2/neu amplification.

Publication types

  • Case Reports

MeSH terms

  • Adenoma, Sweat Gland / drug therapy
  • Adenoma, Sweat Gland / genetics*
  • Adenoma, Sweat Gland / metabolism
  • Adenoma, Sweat Gland / surgery
  • Adult
  • Antibodies, Monoclonal / therapeutic use
  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents / therapeutic use
  • Axilla
  • Gene Amplification*
  • Genes, erbB-2*
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence*
  • Lymph Node Excision
  • Lymphatic Metastasis / genetics*
  • Lymphatic Metastasis / pathology
  • Male
  • Radiotherapy, Adjuvant
  • Sweat Gland Neoplasms / genetics
  • Sweat Gland Neoplasms / pathology*
  • Thoracic Wall
  • Trastuzumab


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents
  • Trastuzumab