Given the rarity of primary lung SRCC, any reported case presents an opportunity to enhance our understanding of the disease. Several features of this case are atypical. First, our search of the literature revealed that our patient was the youngest documented patient with primary lung SRCC in a male ever-smoker. Second, primary SRCC is strongly associated with a solid tumor type.
3 A review of the literature did not reveal any known cases of cavitary primary SRCC. Third, less than 5% of all lung cancers are Pancoast tumors. Of that 5%, about two-thirds are adenocarcinomas, with the remainder being large cell and squamous cell carcinomas.
11 A search of the literature revealed no other reported cases of primary SRCC presenting as a Pancoast tumor. Last, this patient's 21-month survival was uncharacteristically long.
8 These atypical demographic, anatomic, and prognostic features suggest potentially greater variability in the assumed typical behavior of primary lung SRCC. Conversely, the immunohistochemical staining profile of this case was quite typical, reinforcing the reliability of these markers in diagnosing primary lung SRCC.
Although this case involves a disease that most physicians will never encounter, it illustrates several points that are applicable to the everyday practice of medicine. A careful history performed in the emergency department alerted the physician to the possibility of a superior sulcus mass and facilitated the recognition of subtle findings on the chest radiograph. In this age of increased technology use, the value of basic clinical skills can sometimes be underappreciated. This case serves as a reminder of the diagnostic power of a thorough history. Simultaneously, it also provides an example of the utility of technologically advanced diagnostic techniques. The need to separate true SRCC from histopathologic mimics and primary lung SRCC from metastatic SRCC necessitates the use of immunohistochemical staining. An accurate diagnosis of primary lung SRCC in this patient could not have occurred without it.