Calcinosis cutis is a rare, benign and usually asymptomatic condition which may involve any part of the skin and is characterized histologically by deposition of calcium within the dermis. It can be of metastatic, dystrophic, idiopathic or iatrogenic type. Idiopathic calcinosis cutis is cutaneous calcification of unknown cause in the absence of any metabolic disorder.1 Few authors have postulated dystrophic calcification of the epithelial inclusion cysts as the cause.2 Very few case series of this entity have been reported in the literature.3
We report 6 cases of idiopathic calcinosis cutis. The patient’s age ranged from 25 to 71 years. 3 were males and 3 females. Blood reports were normal. Serum calcium, phosphorus, vitamin D were present within normal limits. Lesions were located on the scrotum, scalp, axilla, iliac region with size ranging from 0.5 to 3 cm. Most cases were clinically diagnosed as sebaceous cyst or lipoma. Cytology was performed in one case which showed amorphous granular material. Grossly excised lesions showed whitish chalky deposits.
Histopathological examination showed a variable amount of calcium deposition with surrounding foreign body reaction. Two cases showed the lining of epidermal inclusion cyst along with calcification. Metabolic and connective tissue workup was normal in all cases. None of the cases have reported recurrence till date.
Idiopathic cutaneous calcinosis is a rare, benign, local process, characterized by multiple, painless, hard subcutaneous nodules in the absence of any systemic metabolic disorder.3 Exact incidence is difficult to report as this entity is usually described in the form of individual case reports and limited numbers of case series are available in the literature.4 Multiple theories are proposed for pathogenesis of cutaneous calcinosis by various authors.
There are very few case reports on FNA cytology of idiopathic calcinosis cutis.5, 6 FNA samples yielding abundant calcium have differential diagnosis of calcified fibrous pseudotumor, calcified epidermal cyst, sarcoidosis, tuberculosis, lymphoepithelial lesion, pilomatricoma, osteitis fibrosa cystica, and extra skeletal osteosarcoma etc. Cytological finding of amorphous calcium salts with histiocytes and the appropriate clinical background can help to suspect idiopathic calcinosis cutis which needs confirmation by histology.
Surgical excision is the treatment of choice and has excellent prognosis. Recurrence rate is very low. Incomplete excision may leave microscopic foci of calcification which may recur later.7
This case series is reported to create awareness about the rare entity of idiopathic cutaneous calcinosis which is a benign and local process. It can be diagnosed and managed accurately with clinical, pathological and metabolic correlation. Cytology may be performed in larger lesions. Histopathology is the gold standard for diagnosis. It is completely curable by surgical excision and has very low recurrence if completely excised.