PMC4192926_01
(a) Noncontrast head CT shows a cavitary lesion with perilesional edema and mass effect upon the 4th ventricle. (b) Contrast enhanced MR T1 sequence shows a well circumscribed left cerebellar hemispheric lesion with prominent rim enhancement. There is associated vasogenic edema compressing both the fourth ventricle and medulla
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F1
A head computer tomography (CT) was obtained, which demonstrated a cystic mass in the left cerebellum with perilesional edema [Figure 1]. Further evaluation with contrast enhanced MRI was performed that showed a well circumscribed left cerebellar hemisphere ring enhancing mass on T1 sequences with restricted diffusion, mass effect, and perilesional edema [Figure 1].
(a) Noncontrast head CT status post abscess drainage shows improvement in abscess size and mass affect. There is minimal residual hypodensity present. (b) Acid fast stain shows numerous stained bacilli, which correlated with culture showing pan sensitive mycobacterium tuberculousis
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F2
Numerous acid fast bacilli were seen on acid fast stain, and cultures returned positive for mycobacterium tuberculosis [Figure 2].
Evolution of TB Cerebellar Abscess. (a) Contrast enhanced axial T1 at 4-month follow up shows enhanced thickened and nodular cavity wall, which was unchanged in size or appearance from the postoperative 1 month follow up MR (not shown). (b) Axial T2 FLAIR at 9-month follow up showed increased cavitation size, but with decreased capsule thickness and nodularity. (c) Contrast enhanced axial T1 at 11-month follow up showed decreased size of the lesion, without change in treatment. (d) Contrast enhanced axial T1 at 14-month follow up shows significant reduction in size of previously noted cavitary lesion
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F3
Follow-up MRIs were obtained 1, 4, 9, 11, and 14 months [Figures 3 and 4]. Treatment with rifampicin, isoniazid, and pyrazinamide was continued in order to maximize CNS penetration, and it was noted on the 9-month MRI that the tuberculosis abscess had grown in size from 2.0 x 2.0 x 2.2 to 2.5 x 3.3 x 2.3 cm [Figure 3]. The 11-month follow up MRI showed that the abscess size was decreased to 1.5 x 2.2 x 1.2 cm, and on month 14, the abscess had nearly resolved [Figure 3].
Evolution of TB Cerebellar Abscess on T2 FLAIR Imaging. (a) Contrast enhanced axial T2 FLAIR at 4-month follow up shows significant perilesional edema. (b) Contrast enhanced axial T2 FLAIR at 9-month follow up showed residual perilesional edema, which had decreased since prior study, even though the cavitation size had increased. (c) Contrast enhanced axial T2 FLAIR at 11-month follow up and 14 month follow up (d) showed minimal to no perilesional edema
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F4
Follow-up MRIs were obtained 1, 4, 9, 11, and 14 months [Figures 3 and 4]. While the abscess had grown in size at 9 months, the amount of perilesional edema had decreased [Figure 4b].