Malignant melanoma identified within a pulmonary sequestration- a case report

Pulmonary sequestration (PS) is a congenital lung malformation, which is defined by an anomalous arterial supply from systemic circulation and an absence of communication with the tracheobronchial tree. It is further divided into intralobar and extralobar PS. Pulmonary sequestrations are usually treated surgically, especially if they are symptomatic. Malignant tumors are rarely found within such malformations, mainly adenocarcinomas. We report a case of a malignant melanoma found in a patient operated for intralobar pulmonary sequestration, which is, to the best of our knowledge, the first reported case of a malignant melanoma occurring within a pulmonary sequestration.

We present a case of an 84-year-old male patient who underwent surgical treatment for a symptomatic pulmonary sequestration. The patient was first diagnosed with an intralobar PS two years prior to the surgery by a multislice computed tomography (MSCT) scan. It was located in the left lower lung lobe and had an anomalous arterial supply from an artery arising from the thoracic aorta. Two years later, the patient presented twice to the emergency department with hemoptysis and was thereafter referred to the thoracic surgeon. Another MSCT scan conducted before the surgery showed a newly formed solid lesion within the previously described PS. The thoracic surgeon therefore performed a left lower lobectomy and lymphadenectomy via thoracotomy. Histopathological analysis discovered two melanomas in the specimen, measuring 6 × 5 × 4 cm and 1.7 × 1.7 × 1.5 cm. The patient was referred to an oncologist. A positron emission tomography/computed tomography (PET/CT) scan, along with other diagnostic procedures, didn't show any other signs of malignant disease elsewhere in the body. Several other skin lesions were excised and biopsied, but none have turned out to be melanomas. A year after surgery, the disease disseminated.

Although the origin of the melanoma in this case could not be definitively established, this report demonstrates that pulmonary sequestration may harbor malignant neoplasm and highlights the diagnostic challenges in distinguishing primary pulmonary melanoma from metastatic melanoma. The appearance of a new solid lesion within a pulmonary sequestration necessitates careful evaluation and consideration of surgical resection.