Adenoid cystic carcinoma of lung: An oncologic rarity treated with definitive chemo-radiation

Abstract

Adenoid Cystic Carcinoma is a rare variant of adenocarcinoma originating mainly from salivary glands of the head and neck region distributed throughout the upper aerodigestive tract with a propensity for perineural invasion. Primary adenoid cystic carcinoma of lungs is exceedingly rare accounting for a mere 0.04 to 0.2 percent of all pulmonary neoplasms. The existing scant case reports about this lung malignancy mostly describe small lung lesions managed with upfront surgery followed by adjuvant radiotherapy. We hereby present this case of primary lung parenchymal pathology where the disease was treated with definitive chemo-radiation and to the best of our knowledge; this case is one of the rarest and earliest reports of upfront chemo-radiation in an inoperable primary lung parenchymal ACC. A 43-year-old woman presented with complaints of cough, severe dyspnea, right sided chest pain associated with occasional hemoptysis. Radiographic imaging of thorax showed a large mass lesion with smooth margins measuring 10.2 × 7.3 × 6.8 cm right lower lobe with invasion of adjacent vital structures. Image guided biopsy and immunohistochemical analysis confirmed the diagnosis. She was eventually treated with definitive radiotherapy with concurrent chemotherapy as she was deemed inoperable. Post therapy evaluation by imaging showed a partial response to chemo-radiation, however there was significant symptomatic relief. In view of CD 117 positivity, she has started on oral imatinib mesylate. Presently she is on follow up with a karnofsky performance status of 90%. A thorough review of literature also reveals that our case may be the largest adenoid cystic primary parenchymal pulmonary pathology ever reported.