RESUMO
INTRODUCTION AND IMPORTANCE: Segmental absence of the muscularis propria intestinalis (SAIM) is a rare pathology characterized by a partial or complete absence of the intestinal musculature. Diagnosis requires histological confirmation, and treatment includes urgent laparotomy, resection of affected areas, and end-to-end anastomosis or creation of stomas. The work has been reported in line with the SCARE guideline criteria. CASE REPORT: We present the case of a 31-week preterm newborn with prenatal diagnosis of polyhydramnios and non-immune fetal ascites. Radiological tests confirmed meconium peritonitis, and laparotomy was indicated. The patient had a torpid postoperative course requiring multiple surgeries due to intestinal occlusion and leakage of the anastomosis. Finally, he was discharged with good oral tolerance and bowel function. The anatomopathological examination reported the congenital absence of intestinal muscle with segmental and multifocal distribution. CLINICAL DISCUSSION: Most neonatal cases share similar clinical features, and if SAIM is suspected during surgery, the suspicious areas should be resected to prevent future complications. The prognosis depends on the extent of the lesion, possibility of resecting affected segments, and concomitant pathologies. CONCLUSION: In conclusion, this study aims to describe SAIM based on a clinical case and review of the literature. SAIM is a rare pathology that requires prompt diagnosis and treatment to prevent complications. Surgeons should consider resecting suspicious areas during surgery to prevent future complications.