Treatment of metastatic apocrine sweat gland adenocarcinoma in a cat with association of surgical resection and angular oris reconstruction, extensive lymphadenectomy, electrochemotherapy and systemic chemotherapy

Abstract

Apocrine sweat gland adenocarcinoma (ASGAC) is a rare skin carcinoma in cats. In some cases, this tumor occurs in anatomical sites of challenging wide surgical resection, which increases the need for adjuvant therapies for residual disease. These include radiotherapy or electrochemotherapy (ECT), local treatments for invasive tumors in companion animals often associated with surgery. However, the current literature for ASGAC treatment is limited and there are no reports of ECT as an adjuvant therapy. In this case report, we account for the case of an 11-year-old cat with a history of a non-ulcerated recurrent ASGAC, measuring 1.3 × 1.0 cm, located by the rostral mandibular region. Surgical resection included the angularis oris axial flap for facial reconstruction associated with electroporation of the surgical bed and, post-operatively, in the surgical scar. Histopathological results confirmed the presence of a recurrent ASGAC. Immunostaining revealed cyclooxygenase 2 (COX-2) expression with a score of 6, 50 % positivity in Ki-67, and positive for pan-cytokeratin (PCK AE-1/ AE-3). A selective COX-2 inhibitor was initiated along with systemic chemotherapy with chlorambucil. The local approach including surgery and ECT was chosen due to the unfavorable anatomical site for extensive resection and the unavailability of radiotherapy. Subsequently, carboplatin chemotherapy was required due to metastasis in the mandibular lymph node. This case report supports the effectiveness of a multimodal treatment including surgery, ECT, and chemotherapy in a cat with recurrent ASGAC.