# Unusual Adolescent Abdominal Tumors Presenting With Neuropsychiatric and Massive Abdominopelvic Manifestations: A Report of Two Cases

## TL;DR

This paper reports two rare cases of abdominal tumors in adolescents that presented with unusual symptoms and highlights the importance of thorough diagnosis and multidisciplinary treatment.

## Contribution

The study contributes two unique clinical cases that emphasize the need for high suspicion and advanced imaging in diagnosing atypical abdominal tumors in adolescents.

## Key findings

- A 12-year-old girl with anti-NMDAR encephalitis and an ovarian dermoid cyst showed rapid neurological recovery after surgery and immunotherapy.
- A 14-year-old girl with a 30 cm pelvic mass was diagnosed with an intramural uterine leiomyoma, and symptoms resolved after surgical excision.
- Both cases demonstrate that even benign tumors can cause significant morbidity and require a multidisciplinary approach for optimal outcomes.

## Abstract

Abdominal tumors in adolescence represent a diverse group of pathologies that can present atypically, ranging from neuropsychiatric disturbances to significant abdominal distension. The objective of this study is to report two rare cases that highlight the diagnostic and therapeutic challenges of abdominal tumors in this age group. In the first case, a 12-year-old girl presented with a 10-day history of acute-onset neuropsychiatric symptoms, including hallucinations and cognitive decline, leading to a diagnosis of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Although the initial ultrasound was non-diagnostic, subsequent magnetic resonance imaging (MRI) revealed a 3-cm ovarian dermoid cyst. Prompt surgical resection combined with immunotherapy resulted in rapid neurological improvement, with complete recovery observed within days and sustained at a one-year follow-up. In the second case, a 14-year-old girl exhibited progressive abdominal distension over one month and was found to have a large, predominantly solid pelvic mass. Detailed imaging studies, including computed tomography (CT), delineated a bilobed mass measuring up to 30 cm in maximum dimension. Intraoperative findings confirmed the mass to be an intramural uterine leiomyoma; surgical excision led to the resolution of symptoms and normalization of laboratory parameters (hemoglobin improved from 8.6 g/dL), with no recurrence noted during follow-up. These cases quantitatively underscore that even benign tumors measuring 3 cm and 30 cm, respectively, lead to significant morbidity. Ultimately, our findings emphasize the importance of a high index of suspicion, repeated high-resolution imaging, and a multidisciplinary approach to ensure timely diagnosis and optimal management, thereby contributing to improved clinical strategies in the management of atypical abdominal tumors in adolescents.