Abstract
Tenosynovitis with psammomatous calcification is an extremely rare clinicopathological condition, which is characterized histopathologically by the presence of numerous psammomatous calcifications surrounded by a granulomatous reaction comprising a mixture of histiocytes and fibroblasts. The pathogenesis of this disease remains unclear, although an association with repetitive tendinous injury has been proposed. The present study describes the details of a case in an elderly Japanese female, and, to the best of our knowledge, the first known immunohistochemical analysis of the mechanism underlying psammomatous calcification formation. A 66-year-old Japanese woman presented with pain in the right wrist. The lesion was surgically resected. Histopathological examination revealed a well-circumscribed lesion composed of psammomatous calcification. The calcification was surrounded by histiocytes, and a few multinucleated giant cells and fibroblastic spindle cells. Immunohistochemical study revealed that these histiocytes were positive for cluster of differentiation 163, and the histiocytes and spindle cells surrounding the psammomatous calcification expressed bone morphogenetic protein-1 (BMP-1). Tenosynovitis with psammomatous calcification is hypothesized to be a distinctive subtype of idiopathic calcifying tenosynovitis involving an unusual reactive or degenerative process. BMP-1 has been demonstrated to be involved in the regulation of hard tissue mineralization, and its expression has been suggested to be associated with psammoma formation in papillary thyroid cancer. To the best of our knowledge, the case report within the present study suggested for the first time that BMP-1 expression was associated with development of psammomatous calcification in this condition.