CASE 19

By: Dr. Sattam Lingawi and Dr. Alaa Al-Turkustani

HISTORY: 63-year-old male patients with small cell lung cancer presented with back pain.

What are your findings?

What is the differential diagnosis?

FINDINGS:

Fig. 1 Sagittal T1WI, Fig. 2 Sagittal T2 WI & Fig. 3 sagittal post contrast T1 WI with fat saturation of the lumbar spine demonstrate well-defined intramedullary oval mass at the level of the conus medullaris. It has intermediate signal on T1 WI and bright signal intensity on T2 WI associated with extensive vasogenic edema of the cord extending to the mid thoracic level. The lesion shows strong enhancement on the post gadolinium images with thickening and strong enhancement the cauda equine.

Incidental T12 compression fracture is noted, no enhancement in the vertebral bodies detected.

DIFFERENTIAL DIAGNOSIS:

• Primary Intra medullary mass (eg: ependymoma, astrocytoma & hemangiblastoma).

• Intra medullary metastasis.

DIAGNOSIS:

Intra medullary metastasis from small cell lung cancer.

PEARLS AND DISCUSSION:

Spinal intramedullary neoplasms account for about 4–10% of all central nervous system (CNS) tumors and about 2–4% of CNS glial tumors. Although spinal cord neoplasms constitute only 20% of all intraspinal tumors in the adult population, they constitute 35% of such tumors in children. Most spinal cord neoplasms are malignant, and 90–95% are classified as gliomas. Most of these glial neoplasms are either ependymomas or astrocytomas.

Intramedullary spinal metastases are rare, occurring in only 0.9–2.1% of autopsied cancer patients. They are most commonly located in the cervical cord (45% of cases), followed by the thoracic cord (35%) and the lumbar region (8%). Most metastases are solitary, with an average length of two to three vertebral segments. Lung carcinoma (40–85% of cases) is the most common primary site, followed by breast carcinoma (11%), melanoma (5%), renal cell carcinoma (4%), colorectal carcinoma (3%), and lymphoma (3%); 5% of the primary sites are unknown. Cerebellar medulloblastoma has also been recorded as a causative Source.

FURTHER READING:

1. Kelly K. Koeller, Neoplasms of the Spinal Cord and Filum Terminale: Radiologic-Pathologic Correlation. RadioGraphics 2000; 20:1721–1749

2. M. Judith Donovan Post, Robert M. Quencer. Intramedullary Spinal Cord Metastases, Mainly  of Nonneurogenic Origin. AJNR 8:339-346, March/April 1987