Roentgen Ray 1997

uhrad.com - Musculoskeletal Imaging Case of the Day

Case #4

by: Stephen Hatem, M.D.
Cheryl Petersilge, M.D.

Diagnosis: Metastatic Carcinomatous Arthritis from Mucinous Adenocarcinoma of the Colon.

   

Fig. 4A & 4B Axial CT scans of the right knee at the superior pole of the patella (Fig. 4A) and supracondylar femur (Fig. B) show marked synovial thickening (white arrows) with punctate superficial (black arrow in Fig. 4A) and deep (black arrow in Fig. 4B) calcifications. There is a joint effusion. The bones show no evidence of metastases.

Discussion: Rarely, a patient may present with arthritis as a manifestation of a malignancy. There are several possible etiologies [1-3]:

Of these, metastatic carcinomatous arthritis is the least common, and is rare in association with adenocarcinoma as compared to hematologic malignancies [4]. The synovial involvement is usually secondary to invasion from an adjacent bone metastasis. Synovial metastases without adjacent osseous metastasis is very rare. We were able to find only three reported cases specifically identifying primary synovial involvement [1,2,5]. Although Benhamou et al [3] found 19 reported cases of metastatic arthritis due to adenocarcinoma over a 25 year period, they did not differentiate direct synovial involvement from contiguous spread.

The most common primary tumor associated with metastatic carcinomatous arthritis is bronchogenic carcinoma, followed by breast and gastrointestinal carcinomas [3,6]. Monoarticular disease is the rule [6], with the knee most frequently involved, though involvement of other large and small joints has been reported [3,6]. Clinically, an effusion is present and the joint appears inflamed [1]. Synovial fluid is usually sanguinous and noninflammatory [6]. Cytologic evaluation may reveal malignant cells [2]. Synovial biopsy is often diagnostic[1,2].

In addition to clinical findings which mimic arthritis the radiographic appearance of metastatic carcinomatous arthritis can mimic other entities. The osseous metastases may simulate the periarticular osteopenia, erosions, subchondral cysts, and subchondral sclerosis seen with many arthropathies [1,5]. In the absence of an osseous lesion, as in this case, the differential diagnosis of synovial thickening with numerous punctate calcifications and knee joint effusion includes a spectrum of lesions. This spectrum includes synovial osteochondromatosis, calcium pyrophosphate deposition (CPPD), gout, hydroxyapatite deposition disease (HADD) and, as in this case, metastatic disease.

Synovial osteochondromatosis results from development of nodules of metaplastic cartilage within the synovium [7]. These nodules can ossify and eventually break off to become joint bodies. These bodies typically range in size from several millimeters to several centimeters and have lucent centers. The synovium should have a nodular appearance, unlike the smooth appearance in this case. A joint effusion is rarely present.

With CPPD, synovial calcifications are unusual in the absence of chondrocalcinosis [7]. However, synovial calcification may occasionally be the most significant finding. These calcifications typically are seen as cloud-like densities located within the superficial layers of the synovium at the joint margins. Capsular calcifications may also be present, and usually are linear. Calcifications associated with gout are usually related to tophi or associated CPPD. Although the calcifications of HADD are usually in the periarticular structures, they occasionally may be found within the synovium. The calcifications in this case are present in both the superficial and deep layers of synovium, an unusual distribution for crystal deposition diseases.

The mineralization in this case is within the tumor infiltrated synovium. Soft tissue mineralization in association with neoplasia has been classified into four types [8]:

Mucoid type calcification were the presumed etiology in the presented patient, who had biopsy proven mucinous adenocarcinoma of the colon metastatic to the synovium of his knee.

References:
1. Murray GC, Persellin RH. Metastatic carcinoma presenting as monoarticular
arthritis: a case report and review of the literature. ArthritisRheum 1980; 23: 95-100.

2. Goldenberg DL, Kelley W, Gibbons RG. Metastatic adenocarcinoma of synovium
presenting as an acute arthritis: diagnosis by closed biopsy. Arthritis Rheum 1975; 18: 107-110.

3. Benhamou CL, Tourliere D, Brigant S, et al. Synovial metastasis of an adenocarcinoma
presenting as a shoulder monoarthritis. J Rheumatol 1988; 15: 1031-1033.

4. Harden EA, Moore JO, Haynes BF. Leukemia-associated arthritis: identification
of leukemic cells in synovial fluid using monoclonal and polyclonal antibodies. Arthritis
Rheum 1984; 27: 1306-1308.

5. Meals, RA, Hungerford DS, Stevens MB. Malignant disease mimicking arthritis of the hip.
JAMA 1978; 239: 1070-1071.

6. Fam AG, Kolin A, Lewis AJ. Metastatic carcinomatous arthritis and carcinoma of the lung:
a report of two cases diagnosed by synovial fluid cytology. J Rheumatol 1980; 7: 98-104.

7. Resnick D. Skeletal Metastasis: Diagnosis of Bone and Joint Disorders, 3rd ed. Resnick D and Niwayama G (ed) Philadelphia: W.B. Saunders Company, 1995; 3982-3993

8. Ferrozzi F, Bova D, De Chiara F, et al. CT of secondary neoplasms: unusual
structural features-a pictorial essay. Clin Imaging 1995; 19:131-137.

Return to Day #5

Submitted by:
Stephen F. Hatem M.D.
Cheryl A. Petersilge, M.D.