The answer is c) metastatic disease.

The radiographs shown indeed reveal degenerative changes involving both shoulder girdle regions, with moderate hypertrophic acromioclavicular (AC) joint osteoarthritis (OA) and mild degenerative changes at the insertions points of the rotator cuffs upon the supero-lateral humeral heads. Closer inspection of both radiographs, however, will also reveal numerous irregular pulmonary nodules throughout both upper lung zones seen, in keeping with extensive pulmonary metastatic disease (there was no evidence, on additional imaging, of bony metastatic disease involving the shoulders). A CT scan of the thorax was obtained after seeing these shoulder radiographs (Figures 2a and 2b), which demonstrate the multiple metastatic pulmonary nodules clearly. The CT scan also showed erosive changes (not shown in Fig. 2) involving a number of ribs posteriorly, which would have contributed to the patient’s upper back and shoulder region pain. Subsequent biopsy of one of the larger lung nodules revealed metastatic adenocarcinoma, most likely from colon origin.

This case is a great example of being vigilant to all of the findings on a medical imaging study, not just the areas in clinical question (shoulder girdle articulations in this case). Most findings outside the sphere of interest on medical imaging are incidental and often not clinically significant; but occasionally, as in this case, they’ll lead you to the underlying diagnosis causing the patient’s symptoms.

Metastatic disease was not a prime consideration on this lady’s initial presentation as the original tumour had been surgically removed and treated over 10 years before. But, colon carcinoma is one of those malignancies that can recur very late and claim its victim long after surveillance has ended. The American Society of Clinical Oncology provides guidelines for the follow-up of colon cancer. A medical history, physical examination and CEA (carcinoembryonic antigen) blood test are recommended every 3 to 6 months for 2 years, then every 6 months for 5 years. CT scan of the chest, abdomen and pelvis are suggested for the first 3 years for patients who are at high risk of recurrence (initial pathology revealed poorly differentiated tumours or venous and/or lymphatic invasion) and are also candidates for curative surgery. Annual colonoscopy is also recommended in these patients. Routine PET or ultrasound scanning, chest x-rays, complete blood count or liver function tests aren’t recommended.

The shoulder radiographs shown (Fig. 1a, 1b) reveal moderate bilateral AC joint degenerative changes but no evidence of Grade II AC joint subluxations, so that selection isn’t a viable option. No soft tissue calcifications are seen in the region of the rotator cuff complexes on either side, so calcific tendonitis does not fit (although it does tie in nicely with last month’s “Analyze This” quiz in Parkhurst Exchange, which discussed HADD of the wrist; if you selected this option, consider reviewing last month’s quiz). Glenohumeral dislocations aren’t present so that choice is illogical. The final selection could well be true, in part: bilateral chronic complete rotator cuff tears. There’s superior elevation of the right humeral head in relation to the undersurface of the acromion, which is highly suggestive of a chronic complete rotator cuff tendon tear; however, a similar finding isn’t present on the left side and as such the finding is not bilateral.

References

1. Desch CE et al. J Clin Oncol 2005;23:8512-19.
2. Winawer S et al. Gastroenterology 2003;124:544-60.