The rare entity of cystadenocarcinoma (CAC) in parotid gland: A single-center experience

Case Report: Complete Response of Recurrent and Metastatic Cystadenocarcinoma of the Parotid Gland With a Single Course of Combined Nivolumab and Ipilimumab Therapy

Although cystadenocarcinoma is classified as a low-grade histological subtype of salivary gland carcinoma (SGC), recurrence and metastases sometimes develop. However, standard treatments for advanced cases have not yet been established. Here, we present a case of unresectable local recurrence and cervical lymph node metastases of cystadenocarcinoma of the parotid gland with multiple lung nodules, all of which showed complete response with only a single course of combined nivolumab and ipilimumab therapy. The patient's medical history of metastatic melanoma roused our suspicions that the multiple lung nodules were cystadenocarcinoma metastases or malignant melanoma. Combination therapy was used based on our suspected diagnosis of lung metastases of melanoma although histological examination of the lung nodules could not be performed. While various chemotherapies are used for advanced SGCs including cystadenocarcinoma, overall, the results are unsatisfactory. In contrast, there have not yet been any reports of advanced cystadenocarcinoma of the salivary gland treated with immune checkpoint inhibitors (ICIs). Given that, in our case, a single course of combined ICI therapy induced a complete response in the unresectable and lymph node metastases from the cystadenocarcinoma and the multiple lung nodules, ICIs, including combined therapy, could be a promising treatment for advanced cystadenocarcinoma.

Cytopathology approach to rare salivary gland lesions with oncocytic features

Salivary glands located in the head and neck area are known to have different lesions with prominent oncocytic features. Fine needle aspiration is usually the initial approach in the management of these lesions, whether they represent neoplastic or non-neoplastic processes. Owing to the limited material present upon cytopathologic examination, knowledge of variants and subtypes of various oncocytic lesions that can occur in this area is of major importance to provide the most accurate interpretation to the patients and clinicians. In this article, we selected rare lesions of the salivary glands that may exhibit oncocytic changes, and provided a brief discussion of each one of them, with emphasis on challenges in navigating the differential diagnosis that these cases may pose, from the cytopathology standpoint.