Unusual subcutaneous tumor caused by Dracunculus sp. in Vietnam: integrated clinical, parasitological, imaging, and molecular evidence.

UNLABELLED: Unusual manifestations of Dracunculus infection pose diagnostic challenges, particularly in non-endemic regions. This study reports a descriptive clinical and parasitological investigation of an atypical tumor-like presentation of human dracunculiasis in Vietnam. Clinical, imaging, and parasitological examinations were performed on a patient with an ivory-white cyst initially suspected to be a soft-tissue tumor. The parasite was extracted and identified based on its morphological and molecular features. The active movement of the worm was documented using video recordings. A live nematode was detected within a cyst lesion and identified as Dracunculus sp. based on 18 S rDNA sequence data. To our knowledge, this represents the first documented tumor-like presentation of human dracunculiasis in Vietnam, supported by live visual documentation. This study highlights an atypical manifestation of dracunculiasis that can mimic a soft tissue tumor. Recognition of such atypical presentations is critical for accurate diagnosis and effective management, particularly in regions where Dracunculus infection is rare and may be asymptomatic. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s12639-026-01906-7.