View Abstract

A5638 - Diffuse Large Pulmonary Nodules in a Young Child: Is It Always Metastatic?
Author Block: E. B. Burgener, C. E. Milla; Division of Pulmonary Medicine, Pediatrics, Stanford University School of Medicine, Stanford, CA, United States.
Introduction:
The differential for pulmonary nodules in pediatric patients includes infection, metastatic disease and systemic inflammatory diseases. A primary malignancy in the lungs is very rare in children. We present a case that presented with extensive pulmonary nodules from a primary vascular lesion.
Case Description:
A previously healthy 18 month old male presented with pancytopenia, lytic bone lesions and extensive pulmonary nodules with post-operative respiratory failure and pulmonary hemorrhage. 3 months previously he presented with fatigue, pallor and easy bruising and was found to a hemoglobin of 3mg/dL and thrombocytopenia. Initial bone marrow biopsy was non diagnostic showing hypocellular marrow. After 2 months of dependence on platelet transfusions and repeat non-diagnostic bone marrow biopsy, a full body CT was obtained to evaluate for occult malignancy. Chest CT revealed multiple “cannon ball” hypodense nodules throughout bilateral lung fields in bronchovascular distribution and multiple lytic bone lesions. He developed post-operative respiratory failure and pulmonary hemorrhage after anesthesia for bone biopsy. Open lung biopsy revealed multiple irregular shaped, predominantly thin walled vascular spaces focally lined by hobnail shaped endothelial cells and multiple intravascular papillary projections. Hematology consultation determined his clinical picture and biopsy were most consistent with Cutaneovisceral Angiomatosis with Thrombocytopenia(CAT). He was started on steroids and sirolimus therapy. He was extubated and slowly weaned from positive pressure ventilation to nighttime nasal cannula at time of discharge. On follow up imaging at 6 months his pulmonary nodules had decreased significantly. Sirolimus was discontinued after 9 months and steroids after 12 months. He was weaned from supplemental oxygen at 15 months post diagnosis with normal overnight polysomnogram. Follow up imaging have shown stable pulmonary nodules off therapy. Clinically he has normal growth and development with stable hemoglobin, stable low-normal platelet count and mild dyspnea on exertion. Discussion:
CAT, also known as multifocal lymphangioendotheliomatosis with thrombocyptenia (MLT), is a vascular proliferation disorder affecting various organs and associated with variable thrombocytopenia first described in 2004. The GI tract, lungs, bone, liver, spleen, synovia and skeletal muscles can all be involved. Pulmonary involvement typically manifests before 2 years of age as pulmonary nodules with hemorrhage. Partial to near total regression is described in patients with CAT/MLT with treatment. The natural history of this disorder and progression of pulmonary complications is unknown. This case demonstrates a rare diagnosis where a primary pulmonary process was the cause of large pulmonary nodules.