Psoas muscle infiltration masquerading distant adenocarcinoma

Area of Science:

• Oncology
• Radiology
• Gastroenterology

Background:

• Malignant metastasis to the psoas muscle is an uncommon clinical presentation.
• Psoas muscle involvement by malignancy can mimic infectious processes like psoas abscess.
• Early recognition is crucial for appropriate patient management and prognosis.

Purpose of the Study:

• To report a rare case of psoas muscle metastasis originating from duodenal adenocarcinoma.
• To emphasize the diagnostic challenges and clinical mimicry of iliopsoas metastases presenting as abscess.
• To highlight the importance of considering malignancy in the differential diagnosis of suspected psoas abscess.

Main Methods:

• A case study of a 62-year-old male with a seven-month history of abdominal pain and dysphagia.
• Utilized computed tomography (CT) scans for initial assessment of psoas infiltration.
• Performed CT-guided fine needle aspiration biopsy for histopathological diagnosis.
• Conducted upper endoscopy to identify the primary gastrointestinal malignancy.

Main Results:

• CT revealed right psoas infiltration unresponsive to antibiotics, mimicking abscess.
• Fine needle aspiration biopsy confirmed metastatic undifferentiated adenocarcinoma.
• Upper endoscopy identified a primary duodenal mass, also adenocarcinoma.
• The patient's symptoms and imaging findings were consistent with metastatic disease, not infection.

Conclusions:

• Unresponsiveness to medical therapy for suspected psoas abscess warrants investigation for underlying malignancy.
• Iliopsoas metastases can present clinically and radiologically similar to psoas abscess.
• Further investigations are essential for patients with risk factors and symptoms suggestive of malignancy presenting with psoas imaging findings concerning for abscess.