Title: Atypical Pulmonary Carcinoid Tumor Encapsulated in aStaphylococcus aureus Infection
To the editor:
We present a 13-year-old boy with mild persistent asthma and obstructive
sleep apnea who initially presented with fever, dyspnea, cough, night
sweats and myalgia for 4 days. He reported having an intermittent
“hacking cough” for years. Physical examination was significant for
diffuse crackles in the right lung base, decreased breath sounds and
mild digital clubbing. Initial chest x-ray (CXR) revealed right middle
lobe (RML) and right lower lobe (RLL) opacities with right pleural
effusion interpreted and treated as community acquired pneumonia. He was
followed as an outpatient by his pediatrician and referred to our
pediatric pulmonology clinic months later for persistent RLL atelectasis
and chronic cough. He was well appearing with similar physical
examination findings as described earlier. Laboratory tests including
sweat chloride, cystic fibrosis genetic panel, immunoglobulin levels,
complement, pneumococcal and tetanus titers were normal.
Computerized tomography (CT) of the chest revealed a mass in the right
mainstem bronchus causing distal obstruction of the RML and RLL (Figure
1). Flexible bronchoscopy revealed a round, tan-colored,
cystic-appearing mass completely obstructing the bronchus intermedius
(Figure 2). The mass was attached to the bronchial mucosa and was not
resectable. Bronchoalveolar lavage and biopsy via rigid bronchoscope was
done and grew methicillin-susceptible Staphylococcus aureus(MSSA) without evidence of tumor or other pathology on these initial
specimens (Figure 3A). The patient was treated with a course of
amoxicillin-clavulanate followed by clindamycin for a total of 6 weeks.
A repeat combination flexible and rigid bronchoscopy was performed and
repeat biopsy revealed an atypical pulmonary carcinoid tumor (Figure
3B).
Following the diagnosis, he underwent open thoracotomy with complete
resection of the RML and RLL. There was local metastasis to two
ipsilateral peribronchiolar lymph nodes which were also resected.
Pathology revealed a 4.0 x 1.8cm mass and was strongly chromogranin,
synaptophysin, CD56 and AE1/AE3 positive. Ki67 was 34%. There was
necrosis and 2 mitoses per 2mm2. He denied systemic
carcinoid symptoms such as flushing, edema, diarrhea and palpitations. A
24-hour urine collection for 5-hydroxyindoleacetic acid (5-HIAA) and
whole-body positron emission tomography (PET) scan were negative.
Neuroendocrine tumors (NET) are rare primary neoplasms that affect the
lung, small intestine and rectum. Lung NET are slow-growing masses that
arise from enterochromaffin cells in the bronchial mucosa with an
incidence of 0.2 to 2 cases per 100,0001. Atypical
carcinoid tumors comprise <1% of primary lung neoplasms.
Criteria for diagnosis include presence of carcinoid features, necrosis
(typical carcinoid does not) and the presence of 2 mitosis per
2mm2 on biopsy2. There are limited
case reports in the pediatric population of atypical pulmonary
carcinoid3. Surgical resection remains the only
curative option with a 5-year survival rate of 75% and 10-year survival
rate of 64% in locally resectable masses in adults4with limited data in children. There is no current consensus on first
line chemotherapy and monitoring for disease recurrence.
We present the first case of a pulmonary atypical carcinoid tumor
initially presenting as a MSSA infection in a pediatric patient. The
initial presentation as an MSSA superinfection encapsulating the tumor
delayed the eventual diagnosis, presenting as a diagnostic and
prognostic challenge. Given that metastatic disease in carcinoid tumors
carry a much poorer prognosis, it is of paramount importance that the
underlying malignancy be discovered in a timely manner. There have been
case reports describing fungal superinfection with Aspergillus
masquerading as pulmonary carcinoid tumors,5 but there
are no described cases of bacterial superinfection. When faced with a
bronchial mass that presents as an infection, it is important to treat
the presenting infection and repeat the bronchoscopy and biopsy to
discern whether there is an underlying condition such as malignancy.
Stanley A Lee, MD1
Jessica L Hata, MD2
Matthew P Thompson, DO2
Mary E Fallat, MD3
Kevin M Riggle, MD3
Scott G Bickel, MD1
1Department of Pediatric Pulmonology, University of Louisville,
Louisville, KY
2Department of Pediatric Pathology, University of Louisville,
Louisville, KY
3Department of Pediatric Surgery, University of Louisville, Louisville,
KY