A Rare Manifestation of Secondary Hyperparathyroidism Due to Brown Tumors: A Case Report

Figures & data

Table 1 Patient’s Characteristics

Anthropometrics
Age (years)	58
Sex	Male
Weight (kg)	128
BMI (kg/m^2)	39
Biochemistry	Before treatment	After treatment	Normal values
Calcium	9.13	8.47	8.6–10.0 mg/dl
Phosphate	2.38	3.89	2.5–4.5 mg/dl
Creatinine	1.21	1.8	0.5–1.9 mg/dl
Alkaline phosphatase (ALP)	580	96	35–104 IU/L
25-OH Vitamin D	17.3 ng/mL
Parathyroid hormone (PTH)	1184	103	15–65 pg/mL
TSH	0.03	1.17	0.2–4.2 IU/mL
FT4	1.1	1.07	0.9–1.6 ng/dl

Figure 1 Thorax CT before treatment initiation. Intravenous contrast was administered prior to the exam. Extra pulmonary mass that infiltrates the thoracic cage and the ribs, as shown with the red arrow.

Figure 2 Biopsy from one of the osteolytic rib lesions shows bland fibroblastic spindle cell proliferation admixed with numerous osteoclastic giant cells(arrows), findings which in context are most suggestive of bone changes due to hyperparathyroidism (hematoxylin-eosin, x200).

Figure 3 Thorax CT after i.v contrast, 18 months post treatment showed regression of the tumor in the thoracic cage (from 4.7×3.9 to 4.3×2.8 cm) and the ribs, as shown with the red arrow.

Box 1 Differential Diagnosis of Bone Lesions

Giant cell tumor

Metastatic carcinoma

Brown tumors

Chondrosarcoma

Chondroblastoma

Osteosarcoma

Osteomyelitis

Aneurysmal bone cyst

Eosinophilic granuloma

Infraction

Infection

Non-ossifying fibroma