Sea-Blue histiocytosis

Alternate names

Histiocytosis, sea-blue; Sea-Blue histiocyte disease; Inherited Lipemic Splenomegaly

Definition

Sea-blue histiocytosis, also known as inherited lipemic splenomegaly, is an extremely rare condition characterized by elevated triglyceride levels (hypertriglyceridemia) and an enlarged spleen (splenomegaly). The disorder is so named because certain white blood cells, known as histiocytes, appear bright blue when stained and viewed under the microscope.

Cause

It is one of a group of related fat (lipid) disorders caused by certain changes in the APOE gene.

Inheritance

Autosomal dominant pattern, a 50/50 chance.

The genetic change associated with this condition is inherited in an autosomal dominant manner though other factors, such as a patient's gender, the patient's lipid levels, and the genetic makeup of the other APOE gene may play a role in how the condition is expressed.

Signs and symptoms

Signs and symptoms may include a low platelet count (thrombocytopenia), liver function abnormalities, and heart disease.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Blepharitis(Inflammation of eyelids)
• Edema(Fluid retention)
• Hepatomegaly(Enlarged liver)
• Mediastinal lymphadenopathy(Swollen lymph nodes in center of chest)
• Petechiae
• Sea-blue histiocytosis
• Splenomegaly(Increased spleen size)
• Subcutaneous nodule(Firm lump under the skin)
• Thrombocytopenia(Low platelet count)

30%-79% of people have these symptoms

• Pulmonary infiltrates(Lung infiltrates)

5%-29% of people have these symptoms

• Hyperpigmentation of the skin(Patchy darkened skin)
• Hypopigmentation of the skin(Patchy lightened skin)
• Retinopathy(Noninflammatory retina disease)

Diagnosis

Diagnosis was guided by the morphological finding in bone marrow smears of foamy and sea-blue histiocytes and confirmed by the measurement of acid lysosomal sphingomyelinase activity below normal values.

Treatment

• Management may involve the coordinated care of several different specialists including cardiologists, gastroenterologists, and hematologists.
• Patients with splenomegaly should be careful to avoid contact sports. Removal of the spleen (splenectomy) has been reported to make the condition worse.
• Sea-blue histiocytes can also be a secondary finding associated with a wide range of disorders, including myelodysplastic syndromes, lymphomas, chronic myelogenous leukemia, idiopathic thrombocytopenic purpura, Niemann-Pick disease, and Norum disease.
• In these cases, treatment depends on the underlying disorder.

NIH genetic and rare disease info

• NIH info on Sea-Blue histiocytosis

Sea-Blue histiocytosis is a rare disease.