Synovial Chondromatosis of the Midcarpal Joint: A Case Report and Brief Review of Literature

Abstract

Objective  Synovial chondromatosis is a rare benign proliferative disorder of synovium characterized by the formation of cartilaginous bodies in a joint. The condition typically affects one single large joint. The development of synovial chondromatosis in the joints of hand and wrist is extremely rare.

Case description  In this report, we present a case of synovial chondromatosis arising from the midcarpal joint and the arthroscopic treatment thereof.

Literature review  Owing to its rarity, literature on synovial chondromatosis occurring in the hand and wrist is extremely limited. To our knowledge, no report has been published describing the arthroscopic treatment of an isolated synovial chondromatosis of the midcarpal joint.

Clinical relevance  As synovial chondromatosis of the hand and wrist is extremely rare, and clinical and radiological findings can be nonspecific, the diagnosis might be overlooked initially. The condition does, however, require surgical treatment and thorough follow-up. Thus, awareness of this possible diagnosis among treating physicians is important.

Synovial chondromatosis is a rare benign proliferative disorder of synovium characterized by the formation of cartilaginous bodies in a joint. The condition typically affects one single large joint, such as the knee, elbow, hip, and sporadically the shoulder. The development of synovial chondromatosis in the joints of hand and wrist is extremely rare. Furthermore, as clinical and radiological findings can be nonspecific, especially in early stage disease, the diagnosis might be overlooked initially. ^{1 2 3 4 5 6}

In this report, we present a case of synovial chondromatosis arising from the midcarpal joint. Initially, an alternative diagnosis was proposed, but upon arthroscopic surgery we encountered a myriad of chondromatoid loose bodies intra-articularly. The patient was treated with arthroscopic synovectomy and concomitant removal of all chondromatoid bodies.

As synovial chondromatosis is such a rare entity in the hand and wrist yet does require surgical treatment and thorough follow-up, we present this case and provide a brief summary of available literature.

Case Report

A 35-year-old man reported to our outpatient-clinic with a 6-month history of thumb-sided pain of his left wrist. There was no history of preceding trauma. The symptoms were generally mild yet persistent and consisted of pain upon forceful use of the hand. There was a slight decrease in range of motion. There was no need for the use of analgesics. He had neither medical history nor any complaints of other joints.

Upon clinical examination, there was no swelling nor was there any tenderness upon palpation of the radiocarpal, midcarpal, CMC, or STT joints. Wrist motion was slightly impaired with palmar flexion/extension of 60/50 degrees. End phase movements were painful. Radial and ulnar deviation as well as pronation/supination were unimpaired. Neurovascular examination was normal.

Radiographs of the wrist showed no abnormalities. Magnetic resonance imaging (MRI) of the left wrist showed a synovial thickening of the midcarpal joint, most pronounced at the dorsal and radial aspect ( Fig. 1A–D ).

Fig. 1.

Preoperative T2 weighted coronal ( A, B ) and ( C, D ) axial magnetic resonance imaging of the wrist. The tumor mass shows a high signal and is most prominently at the radial aspect at the level of scapho-trapezium/trapezoid. ( B ) It is a magnification of ( A ) on which loose bodies are present in the synovial fluid. Edema is seen in the trapezium and distal pole of the scaphoid bone as well as the capitate bone.

Under suspicion of synovitis or pigmented villonodular synovitis (PVNS) in the midcarpal joint, we performed a diagnostic arthroscopy to obtain tissue for histopathological examination. Although inflammatory arthropathies were less likely given the history and the aspect on X-ray and MRI, these were part of our differential diagnosis, but these could equally be evaluated arthroscopically. Perioperatively, however, the midcarpal and STT joints contained a myriad of chondral bodies ( Fig. 2A and B ). Thus, we proceeded to a therapeutic intervention in which these were removed by using a shaver blade via conventional radial midcarpal and ulnar midcarpal portals ( Fig. 2C ). Via an additional portal at the scaphotrapezoid joint more chondromatoid bodies were removed, and a synovectomy was performed ( Fig. 2D and E ). The radiocarpal joint was unaffected. Histopathological examination revealed highly vascularized synovium containing clusters of chondrocytes embedded in hyaline cartilage matrix, which is typical for synovial chondromatosis ( Fig. 3A–C ).

Fig. 2.

Arthroscopic views from magnetic-resonance portal, shaver through MU portal. ( A–C ) Synovial chondromatosis; arthroscopic views from MR portal, shaver through scapho-trapezium/trapezoid portal. ( D ) Synovitis present in the ST region with typical rice-body formation. ( E ) Hypervascular synovitis in the ST joint being removed using a shaver blade.

Fig. 3.

Macroscopic image of the synovial chondromatosis in de midcarpal wrist joint showing typical pearl like hyaline nodules. ( A ) Microscopic specimen (hematoxylin and eosin stains staining) showing fragments of highly vascularized synovial tissue with multinodular proliferations of small chondrocytes embedded in hyaline matrix, typical for synovial chondromatosis ( B, C ).

At 6 weeks of follow-up in the outpatient clinic symptoms had resided completely and the patient has a well-functioning wrist. He will be followed-up at low frequent intervals for a prolonged period of time given the high recurrence rate seen in this condition.

Discussion

General

Synovial chondromatosis is considered a benign cartilaginous proliferation arising from (articular) synovium. The condition belongs to a class of benign extraosseous tumors that also comprises tenosynovial chondromatosis and soft-tissue chondromas. These conditions are characterized by the formation of chondromatoid bodies in joints, tendon sheets, or bursae. ^{1 2 4 6} Its etiology is largely unknown. There is a preponderance for the male sex and the condition tends to occur in the third to fifth decade of life. ^{2 7} Synovial chondromatosis is a rare entity in itself but even more so in the wrist joint. It typically affects one single large joint. Most commonly affected joints are the knee, elbow, and hip, respectively. Sporadic cases are described in the shoulder. Involvement of the hand and wrist is extremely rare but has been reported in the DRUJ, midcarpal, pisotriquetral, trapeziometacarpal, metacarpophalangeal, and interphalangeal joints. ^{1 2 3 4 5 6 8}

Only once has an isolated synovial chondromatosis been reported in a case series study by Roulot et al. ⁸ Its treatment, however, was not specified. Mata et al ³ describe involvement of the midcarpal joint in a patient with multiple affected joints, namely the radiocarpal, distal radioulnar, and carpometacarpal joints as well as within flexor tendon sheaths, requiring open surgery. Our case differs from prior reports as it was confined to the midcarpal joint only and the radiocarpal and distal radioulnar joints were unaffected. Therefore, our patient was suitable for arthroscopic treatment, contrary to the other cases in which open surgical procedures were needed.

Whereas synovial chondromatosis has a predilection for large joints, tenosynovial chondromatosis has a strong predilection for the hands and feet and are therefore more often encountered in the wrist. ^{1 2 7} Although this type of chondromatosis arises from the tenosynovium or in a bursa instead of the articular synovium, radiological, and histological findings are similar to those of synovial chondromatosis, and this condition may be an extra-articular counterpart of synovial chondromatosis. ^{1 5 7 9} Malignant transformation of synovial chondromatosis of the hand and wrist into either synovial sarcoma or chondrosarcoma is extremely rare. ^{2 4 8}

Clinical Presentation

Symptoms of synovial chondromatosis of the wrist are nonspecific and generally mild. Pain and joint swelling are mainly encountered can result in functional impairment when the synovitis is severe. Also, the presence of loose chondromatoid or ossified bodies can impair joint mobility. Clinical examination is also nonspecific and mostly shows located pain, swelling, and an impaired range of motion of the affected joint. ^{1 2 4 6 10}

Differential diagnoses include rheumatoid arthritis, crystal arthropathy, psoriatic arthropathy, osteochondritis dissecans, posttraumatic osteochondral proliferations, tuberculous arthritis, periosteal chondroma, synovial sarcoma, chondrosarcoma, PVNS, and degenerative joint disease. ^{1 2 6 8 10}

Imaging

Plain radiography of affected joints may be normal, especially in early stage disease. This often leads to misdiagnosis or under diagnosis of this condition. As calcification of the chondromatoid bodies occur, the lesion becomes detectable on X-rays. Also, soft tissue masses filled with detectable chondromatoid bodies can be present. In long standing, chronic cases, joint destruction, and bone erosion can be observed on X-rays. ^{1 2 5 6 9}

MRI is an appropriate diagnostic tool to detect synovial chondromatosis. MRI commonly shows synovitis with an increase in synovial fluid. In the earlier stages, the cartilaginous nodules in the joint are not yet calcified and the lesion resembles fluid with high signal intensity on T2-weighted MRI scans. As the disease progresses, calcified chondromatoid or osteoid bodies can be seen. ^{1 2 5 8 10} In the case we present, the radiologist initially described synovitis with suspicion of PVNS. Retrospectively, when critically reviewing the images of our case, small dots could be observed, thus raising suspicion of chondromatosis.

Apart from MRI, CT scanning is also considered an appropriate imaging modality to detect synovial chondromatosis as this type of imaging has a high capacity to detect calcified bodies. ^{1 2 5}

Histopathology

Histopathologic evaluation of the specimen is needed to pose the definitive diagnosis. Macroscopically, the nodules found typically vary in size from 1 mm to a few centimetres, have a firm consistence and a glistening white or off white appearance. Microscopic examination shows cartilaginous tissue with clusters or “nodules” of chondrocytes embedded in the hyaline matrix. Sometimes, a mild atypia in the chondrocytes is observed, but this was not so in our case. Histologically, synovial chondromatosis differentiates itself from malignant chondrosarcoma by the loss of mature hyaline matrix and invasive growth in surrounding tissues in the latter. ^{1 6 7 10}

Treatment and Recurrence

The gold standard for treatment of synovial chondromatosis is surgery, with the aim of preserving the joint from degeneration or even destruction. ^{1 10} In as early as 1977, Milgram et al defined synovial chondromatosis as a three-staged disease: stage 1 or early which encompasses synovitis with active synovial proliferation without loose bodies. Stage 2 or transitional which shows synovitis with loose joint bodies, and stage 3 or late synovial chondromatosis in which loose bodies are present, but there no longer is active synovitis. The type of treatment depends on the stage of the disease. In all instances surgery is indicated, however, in the case of a “late” synovial chondromatosis, treatment would suffice with excision of the loose bodies without a synovectomy. In the early and transitional stages, synovectomy is indicated with removal of loose bodies when present. Most cases, as did ours, present in the transitional stage and surgery is generally effective in the treatment of these patients. ^{1 2 8 10} In selected cases with chronic chondromatosis and subsequent joint destruction, patients do not fully recover and have persisting pain and limited motion. ^{1 4 8 10}

Recurrence is common and rates of up to 60% have been reported for (arthro)synovial chondromatosis. From studies on tenosynovial chondromatosis, it is known that recurrence rates in this types of chondromatosis are higher. ^{3 7 10} Furthermore, it has been reported that tenosynovial and synovial chondromatosis can occur within the same patient, and that recurrence of chondromatosis may develop at, or extend to, different anatomical sites. ^{1 3 8} This implies that awareness of this possibility is important for the patient as well as the treating physician, and a prolonged period of low-frequent outpatient clinic follow-up is in place.

Conclusion

In conclusion, owing to its rareness, synovial chondromatosis is a condition that might be misdiagnosed initially when treating patients with nonspecific pain and synovitis of the midcarpal joint, especially when radiological examinations do not show the typical chondromatoid or ossified bodies within the synovitis. Histopathological examination is needed to confirm the diagnosis. If long standing, the presence of intra-articular loose bodies can however lead to degenerative changes within the affected joint. Therefore, surgery with synovectomy and loose body removal is recommended. Also, given the high recurrence rate of the condition, a low-frequent but long period of follow-up is indicated.

Funding Statement

Funding None.