Osteopetrosis misdiagnosed as congenital cytomegalovirus infection: A case report and literature review.

RATIONALE: Infantile malignant osteopetrosis (IMO) (OMIM 259700) is a rare autosomal recessive disease that is caused by defective function of osteoclasts or a reduced number of osteoclasts, resulting in extensive bone sclerosis. The morbidity and mortality rates are extremely high. It may have similar clinical manifestations with congenital cytomegalovirus infection. Due to limited knowledge and heterogenous manifestations, clinical early diagnosis of the disease is challenging. PATIENT CONCERNS: We reported a case of a 3-month, 15-day-old female child who presented with hematologic abnormalities, hepatosplenomegaly, and optic nerve abnormalities. The child was misdiagnosed congenital cytomegalovirus at the initial diagnosis. However, the child's condition did not improve significantly after antiviral treatment. Fortunately, the child was then genetically tested for bone marrow failure disorders. DIAGNOSES: Infantile malignant osteopetrosis. INTERVENTIONS: The treatment involved ganciclovir and transfusion of blood products. However, after 3 weeks of antiviral treatment, the child did not improve significantly. At that time, bone marrow failure disease and immunodeficiency disease gene test report suggested IMO. Her parents refused to do hematopoietic stem cell transplantation. OUTCOMES: Oral valganciclovir and transfusion of blood products treatment was continued. LESSONS: Our report expands the understanding of IMO disease. It is important that patients with clinical features and hematologic findings similar to infection should undergo a thorough clinical evaluation and timely genetic analysis to identify the causative mutation to avoid delays in diagnosis and treatment.