Bone Abstracts

Introduction: System epidermal nevus with hyperkeratosis (SENHK) – congenital epidermal formation characterized by hyperkeratosis, papillomatosis and acanthosis with elongation of intrapapillary epithelial strands. The main manifestations of metabolic bone disorders are system osteoporosis (SO) and violation of vitamin D metabolism. The urgency message is caused by a combination of the two above mentioned diseases in one patient.

Methods: We present 18-year-old patient with a complex problem: SENHK, SO and VDD. The diagnosis is established on the basis of clinical, radiological, biochemical and genetic testing.

Result: Clinically: muscle weakness, bone deformation of the limbs, pathological mobility in the diaphysis of the left femur, the inability for independent movement. Radiological findings: false joint of the left femur, expand growth areas of all long bones with intact areas of enchondral ossification, bone deformities of meta-epiphyseal regions. Biochemical investigations found P1NP 758.3 ng/ml, β-CTx 2.78 ng/ml, osteocalcin 129.6 ng/ml, PTG 40.88 pg/ml, vitamin D 10 nmol/l. X-ray densitometric: decrease of bone density (z-score L1-L4 −3.7, z-score femur neck left – 5.1, right – 5.4). Conservative treatment: pamidronate intravenously three times at intervals of 3 months (one cycle – 1 mg/kg per day for 2 days under the control of calcium serum), then – bivalos (1 pack a day), alpha-D3-Teva (alfacalcidol) – 1 mkg once a day, 10 drops of vitamin D a day – for 3 years. After 4 years seen significant increase muscle strength but deformation of the upper and lower limbs preserved. X-ray densitometric: z-score L1-L4 – 0.7, z-score femur neck left −3.4, right −2.6; biochemical P1NP 177.5 ng/ml, β-CTx 2.38 ng/ml, osteocalcin 91.01 ng/ml, PTG 54.75 pg/ml, vitamin D 13.05 nmol/l. Surgical treatment: resection of the false joint of the left femur, osteosynthesis with intramedullary locking rod.

Discussion: In the literature there are single reports of potential orthopedic manifestations in patients with SENHK. However, we did not encounter information of bone metabolism with the development of system osteoporosis (SO) on the background of the low levels of vitamin D in this disease. We do not exclude the possibility that the combination SENHK and SO are sporadic cases and has no genetic predisposition.

Disclosure: The authors declared no competing interests.