A study of clinical & radiological outcomes of small single enhancing lesions in CT brain - in a tertiary care hospital

Abstract

Introduction Small single enhancing lesion in CT (SSECT) scan as an entity came into existence in India in early 1980, with the advent of CT scan. Tandon et al3 labeled them as intracranial tuberculomas. They identified two types of lesions based on the appearance of the lesion in the C T Scan brain. Small ring and disc lesions were called as immature tuberculomas and large lobulated lesions were called as mature tuberculomas. ATT was invariably started in these patients. Sethi et al5 & Bansal et al6 noted that these lesions disappeared spontaneously without treatment. Natarajan and Arjundas et al37 at the Institute of Neurology, Chennai also noted spontaneous disappearance of these lesions without specific treatment. The exact cause of these lesions could not be deciphered because apart from tuberculoma, cysticercus granuloma, pyogenic abscess, metastases, fungal granuloma, and glioma had been reported to cause similar appearance in CT scan brain as more centers acquired C.T. Scan facility. Hence the exact aetiology of these lesions became a subject of speculation. A significant breakthrough came in 1987 at Vellore 8 when stereo tactic biopsy was done on 15 patients with SSECT. Most of the lesions were identified as cysticercus and none were of tuberculous etiology. Bhargava and Tandon in 1988 and Wadia, Makhalle in 19863,4, found evidence of tuberculous lesions in histopathology. However they failed in defining the size of the lesion. Rajshekhar et al8 then defined a small single lesion based on CT appearance as “A solitary, contrast-enhancing lesion of less than 20- mm diameter lesion without severe cerebral edema (no midline shift)”.this definition is often equated to cysticercous granuloma but there is every possibility that these lesions could be a tuberculoma.