Rare extension of pancreatic pseudocyst with Mycobacterium abscessus into the iliopsoas muscle

Abstract

Pancreatic pseudocyst is a well-known complication of both acute and chronic pancreatitis. Although extension into other anatomical sites is common, extension into the retrofascial space causing an iliopsoas abscess is exceedingly rare. Although its low incidence creates a diagnostic challenge for clinicians, early diagnosis is essential to prevent significant complications and poor patient outcomes. We present a case of iliopsoas abscess with unusual culture fluid growth in the setting of acute on chronic pancreatitis secondary to extension of a pancreatic pseudocyst. We also offer a brief review of the literature and pathophysiology of the condition.

Keywords: Gastrointestinal system; Infection (gastroenterology); Infections; Pancreas and biliary tract; Pancreatitis.

Figure 1

Axial contrast-enhanced CT showing inflammatory changes noted in the mesenteric pancreatic head and body consistent with acute pancreatitis (red arrow).

Figure 2

Coronal contrast-enhanced CT demonstrating well-circumscribed enhancing complex fluid collections consistent with pseudocyst extending into the left lateral flank involving the left iliopsoas muscle group, the largest measuring 5 cm (red arrow).

Figure 3

Purulent fluid obtained following percutaneous drainage of iliopsoas abscess collections.

Figure 4

Coronal contrast-enhanced CT postpercutaneous drainage, showing small residual rim-enhancing areas in lateral left psoas muscle measuring 1.8 cm and in superior left iliacus muscle measuring 1.9 cm, improved from previous images (red arrow).