Cysticercosis masquerading as a buccal mass.

Cysticercosis caused by Taenia solium is endemic in many parts of the world. We present a case of one such lesion which presented itself as an asymptomatic buccal swelling. We present the life cycle of T. solium, the endemic nature of this infection, and the relevance of histological examination to arrive at a diagnosis.

Cysticercosis is a parasitic infection caused by cysticercus cellulosae, the larval form of the cestode, Taenia solium.[1] Humans are the only definitive hosts and pigs are the usual intermediate hosts.[2] The larvae usually infest cerebral tissue, ocular organs, and muscles.[3] Cysts in the oral tissue such as tongue, labial mucosa, buccal mucosa, and floor of the mouth have also been reported.[45] We present a case of oral cysticercosis which presented as an innocuous buccal mass. These lesions mimic a host of benign lesions commonly seen in that site. The importance of histological diagnosis in such a lesion cannot be overstressed for arriving at the diagnosis and providing the appropriate treatment modality.

Case Report

A 35-year-old female patient presented with a complaint of a painless swelling on the right buccal mucosa [Figure 1]. The lesion was visible on extraoral examination as a 2.5 cm×1 cm mass, which was well circumscribed and firm on palpation, midway in the ala-tragal line. The oral mucosa associated with the lesion was normal. The lesion was not fixed to the overlying skin or to the underlying mucosa. A diagnosis of a benign buccal mass with a differential diagnosis of lipoma and schwannoma was made.

Figure 1

Clinical presentation of lesion as a swelling

Routine haematological examination was noncontributory. Under local anesthesia, the mass was excised and sent for histopathologic examination.

A soft tissue mass measuring 1 cm×1.5 cm, firm in consistency and grayish brown in color, was cut into two pieces and processed. The sections were stained with hematoxylin and eosin.

The histological examination showed a thin fibrous capsule with a surrounding membrane enclosing the larval stage of T. solium. The surrounding connective tissue showed a mild inflammatory response and an eosinophilic infiltrate [Figure 2]. A diagnosis of cysticercosis was made and the patient was referred for further evaluation by the physician to rule out further disseminated lesions at other sites.

Figure 2

Histopathologic examination confirming cysticercosis

Discussion

The earliest recorded references to tape worms date to nearly 2000 BC. Protean manifestations of the human–pork tape worm have perplexed medical science for almost 4000 years.[6] These platyhelminths have an egg stage and a larval stage, and then they become adult worms. By consuming inadequately cooked infected pork and raw vegetables, humans acquire the larval form. The cyst wall is destroyed by gastric secretion, releasing one scolex that passes into the small intestine, where it becomes fixed. Embryonated eggs and gravid proglottids are released in the feces, deposited on the soil, and later ingested by the intermediate host, the pig. The animal's gastric secretions destroy the egg wall, and after passage into the duodenum, the larve hatch from the eggs, penetrate the intestinal wall, and are carried by blood or lymph to various tissues. Once in the muscle, the larvae develop into cysticerci. The cystic structure contains a small, invaginated scolex and neck resembling the adult form.[7]

T. solium does not show tropism for any tissue, but has marked tendency to localize in the subcutaneous tissue and muscles, causing palpable and visible nodules.[89]

A large series study of 450 cases by Dixon and Lipscome showed 1.8% of oral cysticercosis.[10] In our case reported here, the buccal mucosa was involved and the lesion presented itself as an asymptomatic nodule. There are no gender preferences for oral cysticercosis. Depending on the anatomical location and the number of invasive oncospheres, cysticercosis can be asymptomatic or produce a plethora of signs and symptoms. Surgical excision and histological pathological examination is essential to confirm the diagnosis of cysticercosis. Cysticercosis is endemic in many parts of the world. An effective method to control cysticercosis may be the use of a good vaccine to prevent the infection in pigs.[11]

As with other zoonotic diseases, collaborative effort of the local and national authorities is needed to control human cysticercosis.[12]

Conclusion

We present a case of oral cysticercosis which presented itself as an asymptomatic submucosal nodule in the buccal mucosa. We stress on the need to include the possibility of cysticercosis in diagnosis of benign nodular masses in the oral cavity, particularly in areas endemic to the presence of T. solium.