Bronchial carcinoid misdiagnosed as COVID pneumonia: a case report

Introduction:

Bronchial carcinoid tumours are rare, slow-growing, malignant, Low-grade neuroendocrine tumours that arise from Enterochromaffin (Kulchitsky) cells and are usually detected typically as indolent and solitary tumours. Approximately 2% of all lung tumours are bronchial carcinoid tumours.

Case presentation:

The authors report a case of 55-years-old man who presented with a history of cough for 1 month and was initially diagnosed with a case of COVID-19. Then he was treated as a case of pneumonia as seen on high-resolution computed tomography. Later, contrast-enhanced computed tomography and bronchoscopy-guided biopsy were done which revealed a right lower lobe neuroendocrine tumour (carcinoid), which was successfully resected.

Clinical discussion:

The majority of typical carcinoids are located in the central airways leading to bronchial obstruction with recurrent pneumonia, chest pain, and wheezing. During the COVID-19 pandemic, lung cancer patients were at higher risk of being affected by COVID-19. This study emphasizes that early identification and differential diagnosis are extremely difficult in the absence of comprehensive study and workup as the clinical and imaging findings of COVID-19 may resemble lung cancer. Although hilar and mediastinal lymph nodes are the most common metastatic sites for typical carcinoids, most lymphadenopathies are caused by a reactive inflammatory reaction.

Conclusion:

Bronchial carcinoids are uncommon, malignant neuroendocrine tumours for which the only curative management is complete surgical resection. With full resection, the result of typical carcinoids with lymph node metastases is favourable.

Introduction

Highlights

• Bronchial carcinoids are slow-growing tumours of Enterochromaffin (Kulchitsky) cells.

• Pneumonia and COVID-19 infection can pose diagnostic difficulty particularly in COVID-19 era.

• Imaging, bronchoscopy, and biopsy are diagnostic modalities.

• Surgical resection is used for management and impacts prognosis.

Bronchial carcinoid tumours are rare, slow-growing, malignant neuroendocrine tumours that arise from Enterochromaffin (Kulchitsky) cells of the respiratory tract epithelial lining. They comprise ~2% of lung tumours and typically develop in the lobar or segmental bronchus. The majority of individuals with carcinoid tumours are smokers, even though no known carcinogen has been identified1. Most pulmonary carcinoids are limited to the main or lobar bronchi. However, regional lymph node involvement is seen in 10%. Particularly typical carcinoids, the prevalence of pulmonary neuroendocrine tumours appears to rise substantially. It is unknown if this is due to an actual rise or a more precise diagnosis when more specialized diagnostic viewing techniques identify asymptomatic carcinoids2. Most carcinoid tumours present gradually and are asymptomatic in 25–39% of patients. Bronchial obstruction and superinfection symptoms may be evident in centrally located tumours. Rarely, in 1% of patients, do carcinoid syndrome and crisis symptoms manifest. Early diagnosis is crucial because surgical excision is the mainstay of treatment and impacts prognosis3.

Herein, we report a case of 55-years-old male who had initially presented with cough and fever, suggesting COVID and then pneumonia. However, his pneumonia did not subside; and bronchoscopy was done, and a mass was seen, whose biopsy revealed to be bronchial carcinoid. The study also aims to highlight the challenges in diagnosing carcinoid tumours in the era of the COVID-19 pandemic and its associated complication. The case has been reported in line with SCARE 2020 guidelines4.

Case presentation

We report a case of 55-years-old male who presented with a history of cough for one month. The cough developed insidiously, was non-productive in nature, associated with on and off fever, and had no aggravating and relieving factors. His history was negative for shortness of breath, hemoptysis, weight loss, fatigue, loss of appetite, and loss of weight.

He is a known case of hypertension and has been under medication for the past year. There is no history of diabetes mellitus and tuberculosis. There is no history of similar illnesses or chronic diseases in the family. He is non-vegetarian by diet, a nonsmoker, and a social drinker.

On examination, he was an averagely built male with a BMI of 26 kg/m². His vital signs were stable, and there were no abnormalities detected on general examination. On chest examination, crepitations were present in the right lower lobe; otherwise, no significant findings were detected on examination of the cardiovascular, neurosensory system, and abdomen.

Haematological investigations, renal function, liver function, and urinalysis were normal. Due to ongoing COVID-19 infections around, RT-PCR was done, which came out to be positive, so he stayed in isolation for 14 days.

At the end of 14 days, repeat PCR was negative. However, his symptoms did not subside. So, sputum culture performed could only show normal flora. High-resolution computed tomography was performed, which revealed features of pneumonia as shown in Figure 1. So, a course of antibiotics consisting of amoxicillin-clavulanate and azithromycin was prescribed.

Figure 1.

HRCT of chest showing consolidations in the left lower lobe. HRCT, high-resolution computed tomography.

However, at the end of a course of antibiotics, his symptoms did not subside, so contrast-enhanced computed tomography was performed, which showed heterogeneously enhancing consolidation with partial volume loss involving posterobasal and lateral basal segments of the right lower lobe with obliteration of lateral basal segmental bronchi and narrowed posterobasal segment as shown in Figure 2. The lesion did not extend into the chest wall. A small fibrotic lesion in the right lung apex was seen. Further, a bronchoscopy was performed which showed endobronchial growth in the right lower lobe, laterobasal segment completely occluding the lumen, and a biopsy was sent, which showed a carcinoid tumour. Immunohistochemistry of the mass was also done, and a final diagnosis of a Grade 2 Neuroendocrine tumour was made.

Figure 2.

CECT of the chest (left-axial section, right-coronal section) showing heterogeneously enhancing consolidation with partial volume loss involving posterobasal and lateral basal segments of the right lower lobe with obliteration of lateral basal segmental bronchi and narrowed posterobasal segment. CECT, contrast-enhanced computed tomography.

Right lower lobectomy was done for the right lower lobe neuroendocrine tumour (carcinoid). The basal segment of the right lower lobe bronchus was cut, and the carcinoid was separated. There was a large subcarinal lymph node that had to be meticulously dissected. Station 9 was also dissected. The chest was closed in layers after 2 (apical and basal drains) of 28 F were placed.

Postoperatively, the patient was managed in the Surgical ICU with IV antibiotics, analgesics, epidural bupivacaine, and oxygen support. He did not have any complications postoperatively. He was shifted to the ward on the fourth postoperative day after his drains were removed, and he was hemodynamically stable. On the seventh postoperative day, the patient was discharged.

Clinical discussion

Carcinoids consist of a spectrum of neuroendocrine tumours, ranging from low-grade malignant typical carcinoids to intermediate atypical carcinoids to high-grade large-cell neuroendocrine carcinoma and small-cell lung carcinoma5. The hormones histamine, prostaglandins, dopamine, kallikrein, and most frequently serotonin are released by carcinoid tumours (5-hydroxytryptamine). 5-hydroxyindoleacetic acid, a 5-hydroxytryptamine metabolite and degradation product, can be eliminated from the body by urination. These hormones can cause a variety of systemic alterations, such as bronchoconstriction, increased gastrointestinal motility, or vasodilatation, which can result in carcinoid syndrome, if they are released into the blood2. Based on histopathologic criteria, carcinoids can be divided into typical and atypical carcinoids6. Clinical symptoms and radiological findings associated with bronchial carcinoids typically are related to bronchial obstruction. Patients mainly present with typical symptoms like hemoptysis, cough, recurrent pulmonary infection, fever, chest discomfort, chest pain, unilateral wheezing, and shortness of breath2.

Lung cancer patients are much more likely than the general population to acquire the COVID-19 virus in the current era of the COVID pandemic. Early detection and differential diagnosis are challenging without comprehensive evaluation and workup, as the clinical and imaging findings of COVID-19 can be identical to lung cancer. The frequent cause of mortality in lung cancer patients being infected with COVID-19 is complications associated with COVID-19, not cancer itself, especially in indolent malignancies like carcinoid tumours7.

In the COVID pandemic era, any respiratory symptoms were considered to be due to COVID pneumonia until proven otherwise. As in the case of our patient, the presence of a tumour only became apparent after investigations such as contrast-enhanced computed tomography chest and bronchoscopy-guided biopsy when the symptoms did not subside. Other presentations, like classic carcinoid syndrome, are highly uncommon in bronchial carcinoids and are generally associated with metastatic disease8. Ten to fifteen percent of patients have regional lymph node metastases at diagnosis9. The most common site of metastasis is the intrathoracic lymph nodes8. Our patient did not have any symptoms of classic carcinoid syndrome, although the tumour had metastasized to the subcarinal lymph nodes and was dissected during the operation.

Early detection is crucial since bronchial carcinoids have a positive long-term outlook after being surgically removed10. The histological grade of the tumour at diagnosis has less of an impact on the prognosis than the nodal status of the tumour. According to Cardillo and colleagues, patients with no nodal involvement (N0) did not experience disease-related mortality, whereas patients with N1 (Ipsilateral tumour extension or metastasis into peribronchial or perihilar nodes as well as intrapulmonary nodes) had 5-year survival rates of 90% and 78.8% for typical and atypical carcinoids, respectively. But, for any N2-containing atypical carcinoids. (Direct extension into or metastases into the ipsilateral mediastinal or subcarinal lymph nodes), 5-year survival was ~22.2%11.

Conclusion

Diagnosing rare lung disorders like carcinoid tumours during the Covid-19 pandemic crisis is extremely difficult and requires a strong index of suspicion and careful diagnostic workup. For individuals with no signs of systemic metastases, the cornerstone of treatment is surgical resection. With complete resection, the prognosis for typical carcinoid tumours with lymph node metastases is excellent. Patients with larger tumours, however, need careful postoperative follow-up because the risk of recurrence is comparatively higher.

Ethical approval

For a case report, the ethical approval is waived at our institution.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in Chief of this journal on request.

Sources of funding

None.

Authors contribution

S.M. led data collection, the concept of the study, contributed to writing the case information. S.K.: literature review, revising, and editing the rough draft into the final manuscript. S.B.: literature review, writing an initial manuscript draft, revising, and editing the manuscript. A.R.R.: literature review, led data collection, revising, and editing the manuscript. A.G.: literature review, led data collection, and concept of study. P.G.: literature review, revising, and editing the manuscript. P.R.: literature review, led data collection, and concept of study. S.P.: literature review, revising, and editing the manuscript. All authors were involved in manuscript drafting and revising, and approved the final version.

Conflicts of interest disclosure

No conflict of interest.

Research registration unique identifying number (UIN)

NA.

Provenance and peer review

Not commissioned, externally peer-reviewed.