Roles of human epidermal growth factor receptor family in pulmonary lymphangioleiomyomatosis

Vasohibin-1 and -2 in pulmonary lymphangioleiomyomatosis (LAM) cells associated with angiogenic and prognostic factors

Lymphangioleiomyomatosis (LAM) is a rare pulmonary neoplasm, clinically associated with dyspnea and respiratory failure. Current therapeutic modalities do not necessarily reach satisfactory outcome and novel therapeutic approaches are currently warranted. Therefore, in this study, we focused on vasohibin-1 (VASH1) and -2 (VASH2); VASH1 terminated and VASH2 promoted angiogenesis. In addition, both VASH1/2 were reported to influence the progression of various human malignancies. We first performed hierarchical clustering analysis to attempt to classify 36 LAM cases into three different clusters according to immunoreactivity of VASH1/2 and other angiogenic and prognostic factors of LAM; VEGFR1/2/3, p-mTOR, p-S6, p-4EBP, ERα, PgR, MMP2, and MMP9. The cluster harboring higher angiogenic factors had higher VASH1/2 status. VASH1 was significantly positively correlated with VEGFR2, MMP9, and p-mTOR (p-value <0.05), and VASH2 with both angiogenic and prognostic factors including VEGFR1, PgR, MMP9, p-mTOR, p-S6, and p-4EBP (p-value <0.05). Subsequent PCR array of angiogenic genes demonstrated that high VASH1 mRNA was significantly positively associated with the status of SPHK1 and TYPM, lower EGF and EFNB2 (p-value <0.05), and high VASH2 mRNA negatively with MMP2 (p-value <0.05). VASH1 was considered to be up-regulated by activation of angiogenesis, whereas VASH2 could influence the angiogenesis and progression of LAM.

A rare pulmonary lymphangioleiomyomatosis disease in a male with tuberous sclerosis complex

Background

Pulmonary Lymphangioleiomyomatosis (LAM) is an uncommon disease and may be associated with tuberous sclerosis complex (TSC). LAM is reported to occur exclusively in females of the premenopausal age group. Here we report a rare entity of lymphangioleiomyomatosis in a male patient of tuberous sclerosis, who developed pneumothorax following mechanical ventilation.

Case summary

A young adult presented to the emergency room with history of recurrent seizures since the 6th month of his age. He was intubated in the emergency room for protection of the airway and was initially maintained on manual ventilation using Bain's circuit. Neuroimaging revealed multiple calcified subcortical nodules and giant cell astrocytoma in left lateral ventricle. On the third day of hospitalization, he developed subcutaneous emphysema on his neck and anterior wall of chest. Contrast-enhanced CT chest revealed presence of subcentimetric thin walled cystic lesions in lungs, pneumomediastinum, right sided pneumothorax, and diffuse subcutaneous emphysema. Right sided pneumothorax was managed by intercostal chest tube drainage. CECT abdomen showed well defined heterogeneously enhancing lesions in right kidney suggestive of angiomyolipoma. A final diagnosis of Lymphangioleiomyomatosis (LAM) in tuberous sclerosis (TSC) was made. Considering the high recurrence of pneumothorax, pleurodesis was done and sirolimus (2 mg per oral OD) was initiated.

Conclusion

Cystic lung disease consistent with LAM is a rare entity in males with TSC, which can be missed easily in patients with extra-pulmonary manifestations. Treating clinician or intensivist should remain vigilant. Active follow-up, chest imaging and pulmonary function testing should be advised to screen the patients for coincidental finding of LAM.