A study was made on 258 cases of cysticercosis, that were examined and diagnosed at the Department of Pathology, College of Medicine, Seoul National University during a period of 9 years from 1968 to 1976 inclusive. There were a total of 35,363 surgical specimens examined during the same period, thus revealing the relative frequency ratio of cysticercosis among surgical accessions to be 0.73%.

The common sites of involvement of cysticercosis were skeletal muscle, subcutaneous tissue, breast, brain and eye in decreasing order of frequency. Painless palpable nodules were the most common initial presentation clinically.

Histopathological staging was attempted based on the host tissue reaction and worm morphology. It was arbitrarily classified into early, intermediate and late stages. In general the morphology of the parasite consisted of a well preserved and compact calcospherules with intact subcuticular muscle layer in the early stage, showing a progressive deterioration of parasitic structures, finally undergoing resorptive process or mummification. The host tissue reation in the early stage was characterized by a diffuse epithelioid cell proliferation with lymphocytic and eosinophilic infiltration without capsule formation. The intermediate stage consisted of a diffuse histiocytic proliferation with well formed outer collagen capsule. The latestage revealed mostly thinned out, well collagenized capsule with scanty lymphocytic infiltration. The parasite in the well formed cyst as usually distorted and often mummified. But the hooklets were relatively preserved up to the late stage.

These finding suggest that the host tissue reacts to the cysticercus worm in fairly uniform fashion, and this fashion appears to have a sequence, i.e., violent lymphohistiocytic response in the initial phase of infection, and undergoing a gradual fibrotic (encapsulating) self-limiting course, finally being stabilized by a dense, acelluar collagen capsule or collapse and absorption.