Conglomerate Ring-Enhancing Lesions are Common in Solitary Neurocysticercosis and do not always Suggest Neurotuberculosis

Clinical and Radiological End Points to Stop Anti-Tubercular Treatment in Central Nervous System Tuberculoma and Predictors of Poor Outcome: A Retrospective Study

The clinical and radiological end points to stop anti-tubercular treatment in central nervous system (CNS) tuberculoma are not known. This retrospective study was done to determine end points to stop anti-tubercular treatment and find the predictors of poor outcome in patients with CNS tuberculoma. Patients who were admitted with a diagnosis of brain/spine tuberculoma between January 2015 and December 2019 and who completed a minimum of 1-year follow-up were enrolled. Clinical and radiological end points to stop anti-tubercular treatment and predictors of death and poor outcome (modified Rankin scale > 2) were analyzed. One hundred and eight patients (male-to-female ratio, 47 [43.5%]:61 [56.5%]; brain tuberculoma, 102; spinal cord tuberculoma, 14; brain and spinal cord tuberculoma, 8) were included in the study. Median duration of anti-tubercular treatment was 24 months. Radiological resolution of tuberculoma (resolution of gadolinium-enhancing lesion, gliosis, calcification, cord atrophy, or syrinx formation) and radiological halt (no increase in size/number of tuberculoma on magnetic resonance imaging scans done 6 months apart) were used as end points to stop anti-tubercular treatment in 69 and 7 patients, respectively. Seven patients stopped their treatment by themselves, and 25 patients died. Altered sensorium, motor weakness, infarcts, hydrocephalus, and constitutional symptoms of tuberculous meningitis were predictors of poor outcome or death in CNS tuberculoma patients. Radiological resolution or radiological halt of brain/spinal cord tuberculoma was a reasonable end point to stop anti-tubercular treatment. However, this may require 24 months or more of anti-tubercular treatment. Associated tuberculous meningitis and its complications portend a poor prognosis.

Complex neurocysticercosis lesions on imaging: Explained through correlative histomorphology

OBJECTIVES

Neurocysticercosis, the commonest neuro-parasite, sometimes presents as complex ring enhancing lesion causing diagnostic dilemma. We aim to establish radio-histo-morphological equivalents of early events in degeneration of the parasite to explain such imaging phenotypes.

METHODS

We compared patterns of degeneration in 23 randomly selected complex NCC on MRI with histo-morphology in 30 cysts obtained from an unrelated post mortem brain.

RESULTS

The anatomy of the parasite and the degenerative patterns of the scolex (hydropic changes, calcification, evagination, and fragmentation) and the cyst wall (undulation, accessory loculi, and frank disruption) were well demonstrated on both. The intact scolex remarkably resembled head of intestinal Taenia. The complex lesions were conglomeration of multiple communicating cysts with a single parent cyst and multiple daughter cysts. The parent cysts contained a solitary variably degenerated scolex, had thicker walls and associated chronic inflammation. The remaining cysts of the lesion complex contained no scolex, had poorly organized walls, turbid contents, and florid perilesional enhancement with leakage of contrast. Three lesions assumed a multi-cystic pseudo-tumorous pattern, of which two resolved into solitary calcific remnants on follow up.

CONCLUSION

Complex lesion in NCC result from degeneration of solitary parasite with perilesional gliosis, surrounded by multiple non-larval daughter cysts inciting acute intra and perilesional inflammation due to enhanced antigenic challenge. Possibly, attempted abortive asexual reproduction by the cellulose cyst as a preterminal event results in a "limited Racemose like transition." Correct interpretation has diagnostic and therapeutic implications as active lesions and their fibrocalcific residue may have greater epileptogenic potential.

Recurrent Neurocysticercosis: Not So Rare

Background

Solitary cysticercus granuloma (SCG) appearing as a single ring-enhancing lesion (SREL) is the most frequently encountered imaging finding in patients of neurocysticercosis (NCC) in India and during follow-up, most of SCGs resolve with or without calcifications. Recurrent SCG have been rarely reported.

Objectives

The aim of our study is to report the incidence of recurrent SCG in a cohort of patients with SCG and postulate the hypothesis.

Materials and methods

This retrospective study included 278 patients with SCG meeting the criteria of NCC. Their medical records and imaging studies were analyzed.

Results

Out of 278 patients, 119 patients with SCG meeting the criteria of NCC with follow-up imaging were included. 15 (12.61%) had recurrent NCC and 104 (87.4%) patients did not have any recurrence during a median follow-up of 14.23 months (range; 0.24 - 113.3) and 25.26 months (range; 3.09- 98.11) respectively. Out of 15 recurrent NCC cases, ten patients had documented imaging resolution or partial regression of previous lesion followed by occurrence of new SCG in the same location, three patients had change in morphology of lesion from solitary discrete REL to solitary conglomerate REL secondary to development of new cysticercus granuloma adjacent to old lesion patients had recurrent lesions adjacent to previous lesion and two patients had new SCG in different locations following regression of old SCGs.

Conclusion

Recurrent SCGs are not uncommon in NCC and recurrence is more likely to occur at the site of initial infection and therefore may be mistaken for persistent infection or other granulomatous lesions.