The term “idiopathic calcifying tenosynovitis” (ICT) refers to a clinically and radiologically defined syndrome of pain and tendinous calcifications, most often involving the shoulder joint. A distinctive subset of ICT cases, termed “tenosynovitis with psammomatous calcifications” (TPC), occurs in the distal extremities and shows characteristic morphology, in particular psammomatous calcifications. As only 14 cases have been reported to date, TPC remains poorly recognized by both pathologists and clinicians. Twenty-three well-characterized cases of TPC along with all available radiologic and clinical information, including follow-up, were collected. Cases occurred in 21 females and 1 male (1 patient of unknown sex), aged 16 to 75 years (mean: 41), and almost exclusively involved the fingers and toes, except for one case in the elbow and one in the knee joint. The lesions ranged from 2 to 30 mm in size (mean: 10 mm). Pain was the most common presenting symptom (12/16 patients). A history of trauma or repetitive activity was present in 6 of 15 patients. None of the individuals was known to have disorders in calcium or phosphate metabolism. Radiographic studies showed a nonspecific, calcified mass. Typical morphologic features of TPC were invariably present, with degenerating tendinous tissue containing psammomatous calcifications, surrounded by a variably cellular, CD68/CD163/CD4-positive histiocyte-rich granulomatous host reaction. HUMARA assay in one case showed a polyclonal pattern. Clinical follow-up (19 patients; mean: 5.2 y; range: 1 to 14 y) showed no local recurrences. In this, the largest study of TPC to date, we confirm striking predilection of this distinctive pseudoneoplasm for the fingers and toes of young to middle-aged women. TPC should be rigorously distinguished from other forms of ICT, which typically involve large, proximal joints, and show simply dystrophic calcification involving tendinous tissues, and from tumoral calcinosis, which also involves large joints and often is associated with calcium and/or phosphate abnormalities. TPC appears to be related to trauma and/or repetitive activity and is cured with simple excision.
*Department of Pathology
†Biomedical Center, Charles University, Faculty of Medicine in Pilsen
‡Bioptical Laboratory Ltd., Pilsen
¶Department of Pathology, Medical Faculty, Masaryk University and St. Anne’s University Hospital, Brno
#Department of Hand & Plastic Surgery, Vysoke nad Jizerou
††Department of Radiology, Faculty of Medicine in Pilsen
‡‡Department of Pathology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
**Department of Hand & Plastic Surgery
§Institute of Pathology, Friedrich-Alexander University Erlangen-Nürnberg, University Hospital, Erlangen, Germany
∥Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
Conflicts of Interest and Source of Funding: Supported in parts by the National Sustainability Program I (NPU I) Nr. LO1503 and by the grant SVV-2018 No. 260 391 provided by the Ministry of Education Youth and Sports of the Czech Republic. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article.
Correspondence: Michael Michal, MD, PhD, Department of Pathology, Charles University, Medical Faculty and Charles University Hospital Plzen, Alej Svobody 80, Pilsen 323 00, Czech Republic (e-mail: email@example.com).