An unusual pain in the hip

Abstract

A 68-year-old previously healthy man presented with increasing right hip pain of 6 months duration. On examination he was found to have a hard mass in the right hip arising from the pelvic bone. Imaging studies were in keeping with a sarcoma arising from the right iliac bone. However, biopsy of this bony lesion confirmed this to be a metastatic adenocarcinoma rather than a primary bone malignancy. Further imaging and a subsequent colonoscopy revealed the primary to be a colonic adenocarcinoma. The unique and unusual nature of this case was the presentation as a solitary bony metastasis from a colonic primary. There is no previously documented report in the literature of such a rare presentation of a colonic adenocarcinoma as a solitary bony lesion mimicking a primary sarcoma in the absence of other signs or symptoms.

Keywords: adenocarcinoma; colon; hip; metastasis; pelvic; solitary.

Figure 1:

X-ray pelvis showing exostosis of the right iliac bone

Figure 2:

MRI right hip showing an exophytic, septated, lobulated mass in the right iliac bone

Figure 3:

Bone tumour biopsy haematoxylin and eosin staining, magnification ×200

Figure 4:

Bone tumour biopsy CDX2, magnification ×200

Figure 5:

CT abdomen demonstrating thickening of the ascending colon

Figure 6:

Colonoscopy showing an ulcerated, fungating, circumferential tumour at the hepatic flexure

Figure 7:

Colonoscopy showing a partially obstructing oozing tumour at the hepatic flexure

Figure 8:

Colon tumour biopsy haematoxylin and eosin staining, magnification ×50

Figure 9:

Colon tumour biopsy haematoxylin and eosin staining with mucin, magnification ×100