ABSTRACT Lagochilascariasis is a neglected neotropical helminthiasis, responsible for human infections through the ingestion of raw or undercooked meat from wild animals infected by larvae encysted in their tissues. It is characterized by a chronic evolution with periods of remission and recurrences, affecting mainly the head and neck regions. It can progress to death by invasion of the central nervous system. It is caused by the Lagochilascaris minor nematode, first described in 1909 and mainly found in the Brazilian Amazon ecosystem, notably in Para State. In May 2010, a 15-year-old female, born in the city of Aveiro, Para State, was hospitalized in the city of Santarem, Para State, presenting with cervical and spinal abscesses and osteolytic lesions at T3-T5 level. During hospitalization, white larvae identified as L. minor were observed in a cervical subcutaneous fistula. After the surgical drainage of abscesses, albendazole 400 mg/day was started, with improvement of symptoms. The patient abandoned the follow-up and in January 2016, during the 20th week of pregnancy, she was readmitted to the Santarem Municipal Hospital with new cervical abscesses in the infra-mammary region, with numerous larvae exiting by subcutaneous left breast fistulas. The antiparasitic treatment was restarted due to possible reactivation of the infection in the spine and dissemination to the central nervous system. Ten weeks after hospital discharge, the patient had resolution of the fistulas and decreased abscesses, without gestational complications. This is the first case report of lagochilascariasis during pregnancy, as well as of involvement of mammary glands.