A PET-positive rapidly growing mass of the abdominal wall after cesarean section with an unexpected diagnosis of vernix caseosa granuloma: a case report

Background: Abdominal wall tumors are rare and include heterogeneous diseases. Among them, desmoid tumors are the most frequent and are often diagnosed in young women during or early after pregnancy; inflammatory response after trauma or microtrauma, such as after cesarean section, may favor their growth. Results: A 37-year-old woman presented with a progressive mass in the abdominal wall after a cesarean section. Positron emission tomography imaging confirmed a positive mass with a high maximum standardized uptake value; a biopsy suggested a myofibroblastic tumor. With continued tumor growth and worsening symptoms, the mass resembled a desmoid tumor; therefore, we proceed with its resection. The final diagnosis was foreign body granuloma as a reaction to the spillage of meconium and keratinous material in the amniotic fluid during cesarean section. Conclusions: The present case provides information on an abdominal wall foreign body granuloma arisen from meconium and vernix caseosa after cesarean section, which presented an atypical clinical picture, mimicking a desmoid, thus requiring a careful diagnostic and treatment approach.