Oncocytic Carcinoid Tumor of the Lung Complicated by Tuberculosis
Oncocytic carcinoid tumor of the lung (OCTL) is a rare type of neuroendocrine carcinoma, accounting for only 1% to 2% of all lung malignancies. This case report describes a unique instance of OCTL complicated by pulmonary tuberculosis (TB), highlighting the diagnostic challenges, clinical management, and potential interplay between these two conditions.
Case Presentation
A 53-year-old non-smoking woman with no significant medical history was admitted to The First Norman Bethune Hospital of Jilin University in June 2017. She reported a 20-day history of intermittent coughing, phlegm, and fever up to 38.7°C following a “cold.” Her symptoms improved with antibiotic treatment, including penicillin and cephalosporin. She also described similar symptoms six months prior, characterized by fever, coughing, chest tightness, and shortness of breath, which worsened with physical activity but improved with medication.
Upon physical examination, the patient exhibited sinus tachycardia with a pulse rate of 118 beats per minute. Her vital signs were otherwise normal, with a body temperature of 37°C, a respiratory rate of 19 breaths per minute, and a blood pressure of 108/71 mmHg. Breath sounds were equal and normal.
Diagnostic Imaging and Findings
Chest computed tomography (CT) revealed shrinkage of the lower lobe of the left lung with areas of calcification [Figure 1A]. The sub-bronchi were narrow or warped, and a shadow with increased density was observed [Figure 1B]. Fiberoptic bronchoscopy identified a new occupying lesion with a smooth surface in a sub-branch of the lower lobe of the right lung, causing closure of the bronchial tube [Figure 1C]. Purulent secretion was noted within the terminus of the left main bronchial tube, where the lumen showed marked stenosis and the mucosa was rough and swollen [Figure 1D].
Pathological and Immunohistochemical Analysis
Immunohistochemical analysis of the biopsy samples revealed positive staining for Ki-67 (+1%), ck-pan (scattered +), CD56 (+), CgA (+), and Syn (+). These findings, combined with the pathological examination, confirmed the diagnosis of OCTL in the sub-bronchial neoplasm of the lower lobe of the right lung [Figure 1E].
Biopsy of the mucosa of the lower lobe of the left lung showed granulomatous inflammation, necrosis, epithelioid cells, and polynucleated giant cells, consistent with TB [Figure 1F]. Acid-fast staining further confirmed the presence of bacilli, solidifying the diagnosis of pulmonary TB.
Laboratory Findings
Blood tests indicated elevated levels of CA125 and C-reactive protein, an increased erythrocyte sedimentation rate, and a normal leukocyte count. These findings supported the presence of an inflammatory process, likely related to TB.
Discussion
OCTL, first reported in 1937, is a specific type of bronchial carcinoid tumor characterized by neuroendocrine differentiation. It originates from the bronchial mucosal Kulchitsky cells, which exhibit eosinophilic cytoplasm due to compensatory hyperplasia of the mitochondria and neurosecretory granules. Mitochondrial lesions are considered the underlying cause of OCTL.
Diagnosis of OCTL primarily relies on pathological examination, which serves as the gold standard, complemented by clinical and imaging findings. Under light microscopy, tumor cells display multiple eosinophilic granules, while electron microscopy reveals neurosecretory granules. The cells are rich in bulky cytoplasmic mitochondria and show positive staining for neuron-specific enolase, synapse, pheochromin A, and cytokeratin on immunohistochemistry. In this case, the diagnosis was confirmed based on the typical appearance of the biopsied cells under light microscopy and the immunohistochemical results.
The coexistence of OCTL and TB in different lobes of the lung presents a unique clinical scenario. While no studies directly explore the relationship between these conditions, the literature suggests that TB lesions may increase the risk of lung cancer and that a history of pulmonary TB can reduce survival among lung cancer patients. One study proposed that carcinoma may reactivate TB, and patients with concomitant TB and lung cancer have a higher mortality rate than those with TB alone. Additionally, the tumor may impair immunity, potentially exacerbating the clinical course of TB.
Management and Prognosis
OCTL is a low-grade malignant lung tumor often treated with surgery due to its insensitivity to chemotherapy. Reported cases treated with surgical resection have shown no metastasis or death during follow-up. Given the good prognosis of controlled TB, the patient was advised to receive TB treatment first, followed by treatment for OCTL once the TB was under control.
However, the rarity of OCTL, the lack of follow-up data, and the absence of previous reports on OCTL complicated by TB make the patient’s prognosis uncertain. Further research and long-term follow-up are necessary to better understand the clinical course and outcomes of patients with both conditions.
Conclusion
This case report highlights the diagnostic and management challenges associated with OCTL complicated by TB. The coexistence of these conditions in different lobes of the lung underscores the importance of comprehensive diagnostic evaluation and tailored treatment strategies. While the relationship between OCTL and TB remains unclear, the potential impact of TB on lung cancer risk and survival warrants further investigation.
doi.org/10.1097/CM9.0000000000000339
Was this helpful?
0 / 0