Extra-articular tenosynovial chondromatosis of the right fifth digit in a 59-year-old man: A case report and literature review.
Tenosynovial chondromatosis of the right fifth digit
A 59-year-old male presented to the Hand Surgery Clinic with a complaint of a painless but irregular mass at the distal interphalangeal joint (DIP) of the right fifth finger that he had noticed since a year ago. He noted that the mass had slowly grown in the last year. The patient reported a slightly reduced range of motion in the DIP joint, however no restrictions in his daily activities. The patient recalled no history of trauma, infection, or overuse of the right hand. On physical examination, a ~ 2 cm multinodular hard mass was palpable over the dorsum and palmar aspect of the DIP joint of the fifth finger (Fig. 1). The range of motion of this finger was slightly reduced in flexion due to mass effect. The patient reported no tenderness or lack of sensation over the area of the lesion. The plain radiographs of the fifth finger showed multiple-calcified bodies of varying size encompassing the middle phalanx from its base to the head (Fig. 1). There is also volar and dorsal osseous scalloping noted of the middle phalanx (Fig. 2). Routine hematological and biochemical tests were unremarkable. Since chondromatosis rarely occurs extra-articularly, the nodules were preliminarily diagnosed as a periosteal chondroma. Surgical excisional biopsy of the nodules was performed under general anesthesia, with a tourniquet applied at the forearm. A longitudinal incision was made on the dorsal aspect of the distal phalanx after a digital block was given. Parts of the mass were dissected and sent for surgical pathology. A small amount of bone destruction was noted on the radial aspect of the middle phalanx; however, no evidence of invasion identified. Histology revealed osteocartilaginous nodules attached to soft tissue and benign-appearing cartilaginous cells in lacunae, (Fig. 3), consistent with a diagnosis of tenosynovial chondromatosis. No signs of malignancy or infection were observed. Complete excisional biopsy was performed one month later. An incision was performed on the palmar aspect of the index finger under the digital nerve block. There were several white and brittle calcified cartilaginous soft tissue masses along the medial and lateral palmar aspect of the right small finger. These masses were densely adherent to the volar plate and flexor digitorum profundus tendon sheath and were safely resected (Fig. 4). Histopathology once again confirmed the diagnosis of tenosynovial chondromatosis. The patient’s postoperative recovery was uneventful and he followed up in the clinic six week after for range of motion exercises.
Preoperative clinical photograph of the palmar aspect (Fig. 1A) of the right-hand showed nodular deformity in the middle phalanx of the fifth finger involving the DIP joint. Initial posteroanterior and oblique radiographs (Fig. 1B and 1C) showed a multinodular calcified mass surrounding the middle phalanx and distal interphalangeal joint. The lateral radiograph (Fig. 2) showed a multinodular calcified mass scalloping the palmar and dorsal aspect of the right fifth finger middle phalanx. In addition, juxta-marginal erosion of the distal phalanx base was also noted. The intraoperative photograph (Fig. 4A) demonstrated calcified cartilaginous soft tissue mass adherent to the tendon sheath. Photograph (Fig. 3A) of the resected specimens and H&E stained histology sections revealed osteocartilaginous nodules attached to connective soft tissue (Fig. 3B) and benign-appearing cartilaginous cells in lacunae (Fig. 3C) consistent with a diagnosis of tenosynovial chondromatosis.
Etiology & Demographics: Primary synovial chondromatosis is characterized histologically by the formation of hyaline cartilage nodules in the subsynovial lining. Synovial chondromatosis may be classified based on the involvement of joint, tendon sheath, or bursa. Tenosynovial chondromatosis (TC) is the extra-articular form of synovial chondromatosis. TC involves the tendon sheath, especially in the hands or feet [1, 2]. Tenosynovial chondromatosis is histologically similar to synovial chondromatosis, but TC is less common and has a higher recurrence rate than the intra-articular form of this disease [1,2]. TC affects the flexor tendons sheaths more frequently than the extensor . To the best of our knowledge, no significant determinant factors such as trauma, infection, repetitive stress, or over usage have been reported to be associated with this entity [2, 4]. Tenosynovial chondromatosis of the fifth finger (as seen in our patient) has only rarely been reported in the medical literature. The demographics of tenosynovial chondromatosis is not well understood due to the rarity of the condition, however, several published studies provide some useful information. A review of 21 patients by Walker found a male predominance before the fifth decade, and a review of 37 patients over 20-years by Fetsch found after the fifth decade with female:male ratio of >2:1 [2, 4]. Even though most literature agrees that TC predominates around the fifth decade of life, there have been cases of TC reported in patients as young as 7 years of age . Clinical & Imaging Findings: The clinical diagnosis of tenosynovial chondromatosis is difficult due to its intermittent nature, slow disease progression, and atypical clinical manifestations. Many patients are asymptomatic. However, if symptoms are present, the two most common symptoms are painless swelling over the span of several months to years and mild point tenderness over the lesion. Other symptoms could include decreased range of motion and trigger finger deformity . The plain radiographs of extra-articular tenosynovial chondromatosis are usually nonspecific, including the existence of calcifications, soft tissue mass, or ossification in the cartilaginous nodules. Additional findings include scalloping of the underlying osseous structures and new bone formation [2, 4, 6, 7]. Our case presents a patient with a nodular mass in the distal fifth finger. Plain film radiographs showed multiple-calcified bodies enclosing the subluxated middle phalanx from its base to the DIP along with volar and dorsal osseous scalloping of the middle phalanx. Other findings, such as erosion of bone surface were also reported . Accurate diagnosis of tenosynovial chondromatosis is challenging on plain film radiography alone. There is a tendency to misclassify tenosynovial chondromatosis with more common look-alike entities such as chondromas of soft parts or periosteal chondromas . Radiographic studies
Tenosynovial chondromatosis is a rare extra-articular counterpart of synovial chondromatosis with a strong predilection for the hands and feet. Clinicians should maintain an index of suspicion for this uncommon entity, as it can be confused with multiple similar presenting etiologies.