Metastatic basal cell carcinoma is a rare entity, having only 230 reported cases in the last century. Pulmonary complications while also reported are rarer still. We present a case of a metastatic basal cell carcinoma presenting as a solitary pulmonary nodule.
An 80 year-old male was noted to have an elevated right hemidiaphragm as well as right middle lobe atelectasis during a preoperative chest radiograph for an Achilles tendon repair (figure 1). Three months subsequently, the patient complained of a persistent cough. A repeat chest radiograph demonstrated this persistent abnormality and the patient was referred for pulmonary evaluation. The patient had a past medical history significant for hypertension, prostate cancer, as well as a 20 pack-year smoking history with a moderate obstructive defect on pulmonary function testing. Additionally, the patient had a basal cell carcinoma of the scalp removed nine years prior. Computed tomography(CT) of the chest revealed a 1.5 centimeter irregular nodule within the right middle lobe as well as atelectasis versus scarring of the right middle and lower lobes. The nodule demonstrated an intense uptake on positron emission tomography(PET). The patient underwent a right thoracotomy with wedge resection of the nodule. Initial frozen section identified the nodule as a possible adenoid cystic carcinoma. Further immunohistochemical staining revealed the nodule to be a basal cell carcinoma, morphologically similar to the lesion resected nine years earlier.
Metastatic basal cell carcinoma is a rare clinical entity, with likely a distinct pathophysiology. The incidence ranges from 0.01-0.1%, and the median time of onset from primary diagnosis appears to be nine years. While basal cell carcinoma typically is slow growing and has an excellent prognosis, metastatic basal cell growth is aggressive and portends a poor prognosis. Median survival after metastasis has been reported to be eight months, with rare patients surviving more than 1.5 years. Primary tumor size appears to correlate with likelihood of metastasis. This is thought to be primarily from lymphatic and or hematogenous spread. Basal cell carcinoma however, displays a stromal dependency, that is, successful implantation to other tissues occurs only if the stroma is included. Interestingly, there is little stroma in the lung and liver, though metastasis to these organs have been described. This suggests that metastatic cancer cells to these organs may have developed a mechanism for stromal independence.
Basal cell carcinoma is a rare clinical entity. We present a case of metastatic basal cell carcinoma presenting as a solitary pulmonary nodule. The time course from primary disease to onset of metastasis in our patient was nine years, which is consistent with current literature. Metastatic basal cell to the lung carries a poor prognosis, and may suggest a novel adaptation, that is, stromal independence.
Jeffrey Kim, None.