Clinical History
A 17-year-old woman presented with a painless, bony hard mass in the gluteal region around the left hip joint, and in the posterior region of the left elbow joint. The central part of the overlying
skin of the gluteal lesion eroded, with discharge of a chalky white material.
Imaging Findings
The patient's serum calcium, phosphate, uric acid, alkaline phosphatase, creatinine and blood urea nitrogen levels were within normal limits. Complete hemogram showed no abnormality. Radiographs of
the left hip and elbow joints (Figure 1) showed irregularly round to oval, radio-dense, juxta-articular calcifications. CT scan (Figure 2) showed in the left gluteal region a large, lobulated
calcified mass. There are fluid–fluid levels in several gluteal lobules consistent with ‘milky calcium’. In the left elbow joint CT scan showed less voluminous amorphous soft-tissue
calcifications. The adjacent joints and the contiguous bones were unaffected. Fine needle aspiration cytology of the gluteal lesion showed amorphous granular material with occasional histiocytes. The
gluteal lesion was surgically resected, the excised mass was whitish in color and milky fluid came out during sectioning. Histopathological examination revealed deeply basophilic amorphous granular
material consistent with calcium deposits surrounded by dense fibrous tissue. Histiocytes were seen occasionally, there were no tumor cell and the histologic diagnosis was tumoral calcinosis. The
lesions did not recur during a one year follow-up after excision.
Discussion
Tumoral calcinosis (TC) is a rare benign disease, characterised by deposits of calcic material in
peri-articular soft tissues. TC mostly affects young, African non-white adults males. The clinical manifestation of the disease is the presence of a spontaneously soft tissue mass in the
periarticular areas. The mass usually is asymptomatic and rarely causes discomfort, tenderness, pain or discharge of calcium salts from the lesions. The trochanteric and gluteal areas of the hip
joint being the most common site in reported series. In the majority of cases the patient's serum calcium, alkaline phosphatase, and the urine calcium are within normal limits. The phosphatemia is
almost always elevated. The pathogenesis of TC is not clear in most cases, and several theories have been advanced on this day. Familial tumoral calcinosis is an autosomal recessive metabolic
disorder associated with elevated levels of serum phosphate. The disease can be caused by recessive mutations in at least two different genes: GalNAc transferase 3 (GALNT3), encoding a
glycosyltransferase that initiates mucin-type O-glycosylation, and fibroblast growth factor 23 (FGF23). Radiological examination plays a key role in the diagnosis. On plain radiographs, tumoral
calcinosis has a typical cloudy and multilobulated appearance. Calcified lumps can grow up to 20 cm in diameter and usually have a smooth or nodular structure. A Pseudocysts and a pseudocapsule may
be seen. The cystic appearance shows fluid-fluid levels caused by calcium layering and commonly termed the sedimentation sign. CT scan better delineates the calcific mass and shows patchy increased
attenuation of affected areas, erosion or osseous destruction by adjacent soft-tissue masses is typically absent. MR imaging demonstrates focal increased signal intensity with multiple small foci
of decreased T2 signal intensity surrounded by a high-signal-intensity ring in the periosseous subcutaneous tissue. Fluid–fluid levels described on MR fat-suppressed T2-weighted images favour
the diagnosis. There are many conditions with similar appearances, including the calcinosis of chronic renal failure, calcinosis universalis, calcific tendonitis, synovial osteochondromatosis,
osteosarcoma, myositis ossificans, tophaceous gout, and calcific myonecrosis. Rule out metabolic diseases, checking phosphate and calcium levels, as well as renal failure. Radiological examination
plays a key role in differentiation as marked nicely in the discussion calcinosis universalis, that affects muscle and fascia planes; calcinosis circumscripta, which is less extensive and located
within the subcutaneous tissue; synovial osteochondromas can associate bone erosion, has intraarticular locations and a typical rings and arcs calcifications; osteosarcoma shows bone destruction
and soft tissue mass; myositis ossificants is usually a delimitated mass with rapid evolution in organized cartilage and bone with lack of loculated appearance; and calcified tophi are less dense
do not show sedimentation, and patients with tumoral calcinosis don’t have hyperuricemia. The treatment of choice is the early complete surgical excision. Spontaneous regression of tumoral
calcinosis in an infant was described once.
Differential Diagnosis List
