A Rare Case of Idiopathic Megacolon and Megarectum

Idiopathic megacolon and megarectum are rare clinical conditions characterized by irreversible dilation of the colon and rectum without an identifiable organic cause. The underlying pathophysiology remains poorly understood, though hypotheses suggest abnormalities in the enteric nervous system or smooth muscle dysfunction. These conditions present significant diagnostic and therapeutic challenges, especially in cases refractory to conservative treatment. We present a case of a 19-year-old male with chronic constipation, progressive abdominal distension, and weight loss over one year, culminating in bowel obstruction. Imaging revealed a massively dilated sigmoid colon and rectum, measuring up to 80 cm in length and filled with approximately 10 kg of fecal matter. The patient underwent a two-stage surgical intervention, including a Hartmann's procedure with sigmoid colectomy and a subsequent completion proctectomy with coloanal anastomosis following symptom recurrence. Histopathological evaluation confirmed the presence of ganglion cells, ruling out Hirschsprung's disease and establishing the diagnosis of idiopathic megacolon and megarectum. Postoperative complications, including a pelvic abscess and surgical site infection, were effectively managed with antibiotics and percutaneous drainage. This case highlights the complexity of diagnosing and managing idiopathic megabowel and emphasizes the importance of individualized surgical interventions. Furthermore, it emphasizes the need for long-term follow-up and calls for further genetic and histological studies to explain the underlying mechanisms and establish standardized management protocols for this challenging condition.