Salivary Gland Secretory Carcinoma With High-Grade Transformation, CDKN2A/B Loss, Distant Metastasis, and Lack of Sustained Response to Crizotinib.

Background: Salivary gland secretory carcinoma is usually a low-grade neoplasm. However, high-grade transformation can occur and has important implications for clinical outcome.

Methods: A patient presented with an enlarging buccal mass. Magnetic resonance imaging (MRI) showed a tumor with a biphasic appearance along the right parotid duct. Local excision and histopathologic examination confirmed the diagnosis of secretory carcinoma with high-grade transformation. ETV6-NTRK3 translocation and loss of CDKN2A/B were identified.

Results: The patient subsequently presented with cough and dyspnea and was found to have pleural metastases. Carboplatin and paclitaxel exacerbated the symptoms. Crizotinib resulted in initial symptomatic and radiographic improvement; however, the patient soon succumbed to progressive intrathoracic disease.

Conclusions: High-grade salivary gland secretory carcinoma can have a biphasic appearance on MRI. Diagnosis is confirmed by the histologic appearance and associated ETV6-NTRK3 fusion. Additional molecular genetic events leading to transformation are unknown; however, loss of CDKN2A/B may have contributed. Treatment with multimodal chemotherapy was of limited benefit.