Cystic brain metastases are unusual. Case series and reports have described cystic brain metastases in association with non-small cell lung cancer (NSCLC). We present the first case of a cystic brain metastasis associated with small cell lung cancer (SCLC). The metastasis was associated with the initial presentation of a lung mass. Biopsy of both the cystic brain lesion and lung mass demonstrated SCLC.
A 70-year-old male was admitted for a total knee replacement. He had a 75 pack-year history of smoking and denied any respiratory symptoms. On admission, the respiratory exam was unremarkable but the neurological examination demonstrated a left temporal field defect and left-sided weakness, both attributed to a prior stroke. Preoperative chest radiograph revealed a right perihilar opacity. Post-operative evaluation of the lung opacity by chest CT scan demonstrated a right middle lobe mass (3.7x4.1x3.5 cm) and right hilar and mediastinal lymphadenopathy. Post-operatively, the patient developed worsening left-sided weakness. A brain MRI showed a large, fluid-filled cystic lesion with a small, enhancing mural nodule (6.9x5.4x5.4 cm) in the right temporal region with mild edema but with midline shift and effacement of hemispheric sulci (Figure 1a). The cystic mass revealed increased T1 signal on the pre-contrast image as opposed to decreased signal expected from pure cystic fluids or CSF (Figure 1b). This increased signal may be explained by its proteinaceous content, cellular infiltrate, and/or subacute blood products. In addition, multiple small solid lesions were noted within the brain with surrounding edema (Figure 2). The patient underwent a craniotomy with decompression of the brain cyst and biopsy of the cyst wall. Cytological analysis of the cyst fluid showed SCLC. The biopsy of the cyst wall also showed SCLC. The patient’s neurological examination significantly improved following cyst decompression. A CT-guided biopsy of the right middle lobe mass confirmed a pure SCLC.
Brain metastases are an important cause of morbidity and mortality in cancer patients, occurring in approximately 10 to 30% of adults with cancer. The lung is the primary site of approximately 70% of cancers that initially present with symptomatic brain metastases. Metastases to the brain are usually symptomatic, the most common being headache (40 to 50%), motor deficit (20 to 40%), cognitive or affective disturbance (30 to 35%) and seizures (10 to 20%). Metastases from breast, colon, and renal cell carcinoma are often single, while lung cancer and malignant melanoma have a greater tendency to produce multiple metastases.Cystic brain metastases from lung carcinoma are unusual. In a series of 25 consecutive patients with NSCLC undergoing open resection of one or more symptomatic brain metastases, 19 were solid and 9 were cystic. In another report of cystic brain metastases preceding a diagnosis of lung carcinoma, only NSCLC was described. A further case report described a cystic lesion with enhancing mural nodule associated with metastatic adenocarcinoma with no localization of the primary. An analysis of cytology from 115 consecutive biopsies of intracranial lesions (95 solid and 20 cystic) demonstrated that 3 of the 20 cystic lesions were malignant of which 2 were primary brain malignancies and the remaining one was a metastatic adenocarcinoma (site unspecified).1.
We describe the first reported case in which SCLC was associated with a cystic brain metastasis. Although cystic brain metastases are associated with NSCLC, this case demonstrates that consideration should be given to SCLC when evaluating a cystic brain lesion.
Vijay Balasubramanian, None.