INTRODUCTION:Carcinoid Syndrome is characterized by cutaneous flushing, bronchospasm, chronic diarrhea, and cardiac valvular diseases. Tumors resulting in Carcinoid Syndrome are commonly reported in the gastrointestinal tract. Reports of Carcinoid Syndrome secondary to lung carcinoids are rare.
CASE PRESENTATION:A 36 year-old female was referred to the thoracic surgeon with abnormal Computerized Tomography (CT) chest. Presenting symptoms were episodes of fever, flu-like symptoms, hot flashes, acne, shortness of breath and wheezing on exertion, and episodic diarrhea.The patient’s medical history was significant for bronchitis and pneumonia, with no history of smoking and non-contributory family history. Over the past year, the primary care physician had unsuccessfully treated the patient’s symptoms with antibiotic courses and broncho-dilators and finally resorted to CT chest, abdomen, and pelvis with contrast and pulmonary function test (PFT). The chest CT revealed mild right-sided pleural effusion, narrowing of the right bronchus, and evidence of consolidation in the inferior aspect of the right hilum. The suggested diagnosis was malignancy with meta-static lesions. The PFT showed moderate obstructive pulmonary disease. (The CT also showed a 1.5 cm nodular density in the right lobe of the liver which was later identified as a hemangioma through followup magnetic-resonance imaging (MRI) with contrast.)Given her age and recurrent symptoms, the patient was scheduled for flexible bronchoscopy, which revealed partially obstructive submucosal tumor in the bronchus intermedius, past the take-off of the right upper lobe. There was narrowing of the right middle lobe orifice; the tumor appeared to be a pulmonary carcinoma with surrounding angiogenesis. No biopsy was performed because of the risk of bleeding. Cytology of the lavage samples were non-diagnostic. The patient’s bloodwork revealed elevated serotonin levels (502 ng/ml), leading to diagnosis of carcinoid syndrome.Video assisted thoracoscopy (VATS)-assisted right-lower-lobe lobectomy was performed, revealing a 4x3x3 cm carcinoid tumor with no lymphnodal involvement. Subsequent octeotride scan revealed no other focus of ectopic hormone production. The patient’s serotonin levels continued to decline post-surgery, and the patient has since remained symptom-free.
DISCUSSIONS:Carcinoid Syndrome is a well-defined clinical entity characterized by cutaneous flushing, bronchospasm, chronic diarrhea, and cardiac valvular diseases in late stages. Although the precise biochemical mechanism is not understood, the Syndrome is believed to be secondary to excessive production of serotonin.Carcinoid tumors resulting in Carcinoid Syndrome are commonly reported in the gastrointestinal tract or are associated with liver metastatis. Lung carcinoids can also produce ectopic hormones. In our literature search, we came across multiple reports of lung tumors producing adrenocorticotrophin, growth hormone, and glucogon, respectively resulting in diabetes, acromegaly, and Cushing’s Syndrome. Reports of seratonin-producing lung carcinoids are rare, possibly because the lungs contain high levels of monoamine oxidase which metabolizes serotonin. In our patient, the role of lung carcinoid in causing Carcinoid Syndrome symptoms became likely because of the absence of other tumor site on the octeotride scan; the diagnosis was confirmed by resolution of symptoms and decreased serotonin levels after surgery to remove the lung carcinoid.
CONCLUSION:Lung carcinoids associated with Carcinoid Syndrome are rare, likely because monoamine oxidase metabolizes lung serotonin. We do not know whether lung carcinoids simply do not produce serotonin or whether they regularly produce serotonin at levels that are readily metabolized prior to expression of symptoms. A detailed clinical history and high level of suspicion brought by absence of other causes are required for accurate diagnosis.
DISCLOSURE:Sukriti Singhal, No Financial Disclosure Information; No Product/Research Disclosure Information