Localization of a Corticotropin-Secreting Tumor by Thoracoscopic Pulmonary Venous Sampling
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《新英格兰医药杂志》
To the Editor: Corticotropin-secreting pulmonary tumors are an uncommon cause of Cushing's syndrome.1 Precise localization of ectopic (nonpituitary) sources of corticotropin can be difficult: radiologic studies are often nonspecific, and surgical exploration by standard thoracotomy is associated with morbidity. Video-assisted thoracic surgery (VATS) is gaining popularity for anatomical and nonanatomical pulmonary resections. We describe a patient with Cushing's syndrome due to ectopic secretion from a single pulmonary carcinoid; percutaneous sampling of blood from the pulmonary veins by VATS to determine corticotropin levels permitted precise localization of the tumor and confirmed the completeness of the resection.
A 25-year-old man was examined because of weight gain, hypertension, hirsutism, and purple striae of the abdomen and thighs. The initial results of biochemical evaluation included an elevated 24-hour urinary cortisol level (237 μg; normal range, <105) and an elevated corticotropin level (53.6 ng per liter; normal range, 6 to 48). The high cortisol levels could not be suppressed by dexamethasone administration. Extensive workup for a pituitary adenoma was negative.
Computed tomographic scanning of the chest revealed two lesions larger than 1.0 cm — one in the superior segment of the right lower lobe and one in the lingula. Both lesions had moderately increased uptake on octreotide scintigraphy.
The right inferior and left superior pulmonary veins were punctured to allow measurement of corticotropin levels by the VATS technique. Sampling from the pulmonary veins was done before and after segmentectomy of the pulmonary nodule on the right side and wedge resection of the lingular nodule. The right side was approached first, followed by the left. The lesion in the right lower lobe was later determined to be a carcinoid tumor and that in the lingula a cryptococcal lesion.
The corticotropin level had been markedly elevated in the right lower pulmonary vein but decreased by 85 percent after the right superior segmentectomy (Figure 1). Wedge resection of the nodule in the lingula did not result in any change in the corticotropin level. The patient had a biochemical cure, with corticotropin and cortisol levels of 9 ng per liter and 2 μg per deciliter by postoperative day 1. The cutaneous, hemodynamic, and psychiatric symptoms related to the hypercortisolism resolved after surgery and have not recurred during six months of follow-up.
Figure 1. Corticotropin Levels before and after Wedge Resection.
Pulmonary ectopic sources of corticotropin are well recognized and include small-cell cancer of the lung and bronchial adenoma; however, nonspecific lung nodules may make radiologic confirmation difficult. This case demonstrates the use of a minimally invasive technique to sample blood from the pulmonary veins (in a fashion analogous to sampling from the inferior petrosal vein) to localize an ectopic pulmonary source of corticotropin and determine its cause.
Lan Vu, M.D.
Pierre R. Theodore, M.D.
University of California at San Francisco
San Francisco, CA 94131
theodorep@surgery.ucsf.edu
A 25-year-old man was examined because of weight gain, hypertension, hirsutism, and purple striae of the abdomen and thighs. The initial results of biochemical evaluation included an elevated 24-hour urinary cortisol level (237 μg; normal range, <105) and an elevated corticotropin level (53.6 ng per liter; normal range, 6 to 48). The high cortisol levels could not be suppressed by dexamethasone administration. Extensive workup for a pituitary adenoma was negative.
Computed tomographic scanning of the chest revealed two lesions larger than 1.0 cm — one in the superior segment of the right lower lobe and one in the lingula. Both lesions had moderately increased uptake on octreotide scintigraphy.
The right inferior and left superior pulmonary veins were punctured to allow measurement of corticotropin levels by the VATS technique. Sampling from the pulmonary veins was done before and after segmentectomy of the pulmonary nodule on the right side and wedge resection of the lingular nodule. The right side was approached first, followed by the left. The lesion in the right lower lobe was later determined to be a carcinoid tumor and that in the lingula a cryptococcal lesion.
The corticotropin level had been markedly elevated in the right lower pulmonary vein but decreased by 85 percent after the right superior segmentectomy (Figure 1). Wedge resection of the nodule in the lingula did not result in any change in the corticotropin level. The patient had a biochemical cure, with corticotropin and cortisol levels of 9 ng per liter and 2 μg per deciliter by postoperative day 1. The cutaneous, hemodynamic, and psychiatric symptoms related to the hypercortisolism resolved after surgery and have not recurred during six months of follow-up.
Figure 1. Corticotropin Levels before and after Wedge Resection.
Pulmonary ectopic sources of corticotropin are well recognized and include small-cell cancer of the lung and bronchial adenoma; however, nonspecific lung nodules may make radiologic confirmation difficult. This case demonstrates the use of a minimally invasive technique to sample blood from the pulmonary veins (in a fashion analogous to sampling from the inferior petrosal vein) to localize an ectopic pulmonary source of corticotropin and determine its cause.
Lan Vu, M.D.
Pierre R. Theodore, M.D.
University of California at San Francisco
San Francisco, CA 94131
theodorep@surgery.ucsf.edu