MSK for Thursday, April 10th, 2025

History

A five-year-old child presented to an outside emergency room with his parents with concern for developing swelling and erythema of the left hand over the past day. Initial radiographs performed in the outside ED raised concern for a possible foreign body in the soft tissues between the bases of the index and middle fingers. Based on these findings, the patient was discharged with a course of antibiotics and a referral to pediatric hand surgery. 

 Upon evaluation by the hand surgery team the following day, the patient exhibited progressive swelling, erythema, and pain despite antibiotic therapy. Notably, he remained afebrile and showed no systemic signs of infection. There was no reported history of trauma or external skin injury. 

Physical examination revealed a healthy-appearing boy with erythema, edema, and tenderness localized to the left second webspace extending into both the volar and dorsal aspects of the first metacarpophalangeal (MCP) joint. The overlying skin was intact without lacerations, abrasions, or skin breakdown. Although there was no palpable foreign body, examination was limited by tenderness. The fingers were warm and well-perfused. Subsequent review of the initial radiographs by a pediatric musculoskeletal radiologist suggested that the findings were unlikely to reflect a retained foreign body and was more reflective of soft tissue calcification. Clinically, the surgeons wanted to rule out osteomyelitis, so MRI with and without contrast was requested and performed. 

Images (Click any image to enlarge)

Question

In the setting of acute calcific periarthritis, which of the following MRI findings most accurately describes the appearance of calcifications and surrounding tissue during the acute symptomatic phase?

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Correct answer

Calcifications are hypointense on T2-weighted images but may appear hyperintense due to surrounding inflammatory infiltrate, accompanied by adjacent soft tissue edema.

Discussion

Calcific periarthritis is a disease process characterized by abnormal calcium deposition in periarticular soft tissues. It most commonly affects the rotator cuff tendons, where it is most often described as “calcific tendinitis,” but can affect additional periarticular structures such as periarticular ligaments, bursae, and joint capsules throughout the body. Although primarily an adult condition – with an average age of 45 years – it is rare in pediatric patients (1,2). Typically confined to a single joint, it presents with acute pain, erythema, edema, and reduced range of motion. Infrequently, systemic signs such as fever, chills, and elevated inflammatory markers (e.g., C-reactive protein and erythrocyte sedimentation rate) may mimic infection. The condition progresses through four phases, with the acute phase being the most symptomatic eventually terminating in resorptive and healing phases (1,3).

Calcific periarthritis may be clinically suspected, however imaging plays a central role in the diagnosis and is often most useful for excluding alternative pathologies. Radiographic evaluation of the affected joint will most commonly reveal amorphous periarticular calcifications lacking internal trabeculae or a defined cortex (1,3,4). Alternative diagnoses should be thoroughly evaluated, particularly when cross-sectional imaging is available. CT is not commonly obtained for evaluation, especially in the pediatric population, however imaging findings are often synonymous with radiographic findings. MRI may be beneficial due to its ability to assess the periarticular soft tissues and assist in excluding other diagnoses. Calcific deposits are typically hypointense on both T1- and T2-weighted images, though occasional T2 hyperintensity may indicate edema. In the acute phase, adjacent soft tissues exhibit an edema-like signal and enhancement (1,3,5). Osseous erosion and bone marrow edema are not typical findings. Similar clinical presentations include septic arthritis, osteomyelitis, and soft tissue infections, as examples.

This self-limited process typically sees symptom reduction within 4-7 days and complete resolution by 3-4 weeks (1,6). Management is often conservative, with an emphasis on symptomatic relief with non-steroidal analgesics and joint rest (4,5). Repeat imaging at 3–4 weeks may show partial or complete resorption of calcific deposits, and recurrence is rare (5). Accurate diagnosis is essential to limit unnecessary antibiotic or invasive treatments. This diagnosis, although exceedingly rare in the pediatric population, should be considered in the appropriate clinical and imaging context.

Differential diagnosis

Similar clinical presentations include septic arthritis, osteomyelitis, soft tissue infections, trauma, gout, and tumoral calcinosis, as examples. Cross-sectional imaging can help with differentiating this entity from others, although clinical history and presentation is essential to the diagnosis.

Additional images

References

• 1. Dimmick S, Hayter C, Linklater J. Acute calcific periarthritis-a commonly misdiagnosed pathology. Skeletal Radiol. 2022;51(8):1553-1561. doi:10.1007/s00256-022-04006-8
• 2. Millon SJ, Bush DC, Harrington TM. Acute calcific tendinitis in a child: a case report. J Hand Surg Am. 1993;18(4):592-593. doi:10.1016/0363-5023(93)90296-F
• 3. Chung CB, Gentili A, Chew FS. Calcific tendinosis and periarthritis: classic magnetic resonance imaging appearance and associated findings. J Comput Assist Tomogr. 2004;28(3):390-396. doi:10.1097/00004728-200405000-00015
• 4. Nikci V, Doumas C. Calcium deposits in the hand and wrist. J Am Acad Orthop Surg. 2015;23(2):87-94. doi:10.5435/JAAOS-D-14-00001
• 5. Tomori Y, Nanno M, Takai S. Acute calcific periarthritis of the proximal phalangeal joint on the fifth finger. Medicine. 2020;99(31):e21477. doi:10.1097/MD.0000000000021477
• 6. Lehmer LM, Ragsdale BD. Calcific periarthritis: more than a shoulder problem: a series of fifteen cases. J Bone Joint Surg Am. 2012;94(21):e157. doi:10.2106/JBJS.K.00874