MCH Levels in Cystic Hygroma
Cystic hygroma itself does not affect mean corpuscular hemoglobin (MCH) levels—a child or young adult with an isolated cystic hygroma should have completely normal MCH values within the standard reference range for their age and sex. 1
Understanding the Distinction
Cystic hygroma (more accurately termed lymphatic malformation) is a congenital structural abnormality of the lymphatic system, not a hematologic condition. 1 These lesions:
- Result from lack of communication between the lymphatic system and venous drainage, typically in the neck region 1
- Are classified as vascular malformations (specifically lymphatic malformations), not vascular tumors 1
- Do not involve bone marrow dysfunction or red blood cell production abnormalities 1
Expected Normal MCH Values by Age
For a healthy child or young adult with isolated cystic hygroma, MCH should fall within these normal ranges 1:
- 6 months to 2 years: Hemoglobin ~12.0 g/dL (MCH proportional to age-appropriate values)
- 2 to 6 years: Hemoglobin ~12.5 g/dL
- 6 to 12 years: Hemoglobin ~13.5 g/dL
- 12 to 18 years (male): Hemoglobin ~14.5 g/dL
- Adult male/post-menopausal female: Hemoglobin ~15.5 g/dL 1
MCH typically ranges from approximately 27-31 pg in normal children and adults, calculated as hemoglobin concentration divided by red blood cell count. 1
When to Suspect Hematologic Abnormalities
If a patient with cystic hygroma presents with abnormal MCH, investigate for unrelated causes rather than attributing it to the lymphatic malformation itself. 1
Low MCH indicates:
- Iron deficiency (most common cause—MCH decreases along with MCV) 2
- Thalassemia trait (alpha or beta thalassemia, particularly if MCV is disproportionately low relative to anemia) 2
- Chronic inflammatory conditions (less common) 2
High MCH suggests:
- Hemolytic anemia (requires critical peripheral smear evaluation) 3
- Vitamin B12 or folate deficiency (macrocytic anemia) 1
- Laboratory artifact (values significantly above reference range are not physiologically possible) 3
Special Consideration: Turner Syndrome
The only scenario where cystic hygroma might be associated with hematologic findings is when it occurs as part of Turner syndrome (present in 50-80% of cases with cystic hygroma). 1 However, even in Turner syndrome, MCH levels are typically normal unless there is a separate, unrelated cause of anemia. 1
Diagnostic Pitfall to Avoid
Do not order extensive hematologic workup solely because a patient has cystic hygroma—the lymphatic malformation does not cause anemia or alter red blood cell indices. 1 If anemia is present, evaluate it as you would in any other patient using standard diagnostic algorithms based on MCV, MCH, reticulocyte count, and iron studies. 1, 2