We present the case of a 18 year old male presenting with cough, fever and left-sided pleuritic chest pain.
An 18-year-old otherwise healthy 2 pack year smoker male presented to Emergency Room with a two-month history of cough with fever, chills and left-sided pleuritic pain on coughing. Chest X-ray done as outpatient Showed Left upper lobe infilterate. PPD was negative and a course of oral antibiotics had failed to resolve symptomsIn ER, patient had a temperature of 103°F, blood pressure of 116/60, pulse 120/min. and a respiratory rate of 25/min. and a room air saturation of 90%. Systemic examination was significant for markedly diminished breath sounds in the left upper lung fields along with dullness on percussion in the same areas. Cardiac, neurologic, skin and examination of the extremities were unremarkable.. Initial ER Chest Xray and CT scan revealed a dense consolidation in the left upper lung with pleural effusion.Thoracentesis was done which revealed an exudative pleural effusion with a pH of 6.7, WBC count of 4700, RBC count 1.9 m/cu.mm, glucose less than 20, LDH of 12285, protein of 4.9 gm/dl. A chest tube was placed for drainage of empyema. Bronchoscopy revealed a polypoid 1x1 cm endobronchial tumor in the left main stem bronchus. Multiple endobronchial biopsies were done and sent for histopathological examination. The histopathological diagnosis of low-grade Mucoepidermoid carcinoma of salivary gland origin was made.DISCUSSION: Mucoepidermoid tumors (MET) are rare pulmonary neoplasms. Miller et al1 described their incidence as 0.15% of primary lung cancers. METs were first described in the salivary glands where they were presumed to arise from the excretory ducts of the salivary glands. Occurrence of these tumors in the lungs was first described by Smetana et al2The clinical presentation of MET is not specific and it can present with symptoms like recurrent infection, new onset of shortness of breath and wheezing and may be initially misdiagnosed as a case of adult onset asthma.The tumors characteristically show a solid growth pattern composed of epidermoid cells distributed in sheets that obliterate the normal lung parenchyma. Admixed with this epidermoid cell proliferation are areas showing cystic structures lined by mucin producing epithelium and often containing mucinous material in the lumen.TREATMENT and PROGNOSIS: Surgery alone is sufficient for resectable low-grade tumors, whereas adjuvant radiation or chemotherapy or both are recommended for resectable high grade METs. In difficult cases pneumonectomy may be the only alternative. High grade METs should be treated as well differentiated non-small cell or squamous cell carcinoma, by lobectomy with nodal sampling if surgical resection is not possible or incomplete.Overall 5-year survival rate for the primary Mucoepidermoid tumors of the lung is 45% 1. High grade Mucoepidermoid tumors has a 100% mortality with a median survival of 5 months.
Because of non specific symptoms, diagnosis of METs is often delayed. High index of suspicion is required for diagnosis of Mucopepidermoid tumor
Outpatient chest X-ray.
Chest X-ray and CT scan done in ER, showing dense consolidation with effusion in left lung.
The low-grade mucoepidermoid tumor consists of cytologically bland tubules, devoid of mitosis, nuclear pleomorphism or necrosis. H&E Stain. Magnification x 200
Intracytoplasmic mucin is evident in tumor cells on Mucicarmine stain. Magnification x 400
Criteria for differentiating between high and low grade mucoepidermoid tumorsFeatureLow Grade METHigh Grade METAge at presentationAve.age 34.8 years (usu. <30 Yr. Old.)Ave. age 44.5 years (Usu. >30 yr.)SymptomsSame in both groups including fever, SOB, cough, hemoptysis and wheezing. Same in both groups including fever, SOB, cough, hemoptysis and wheezing.LocationNo particular lung lobar or segmental predilection.HistopathologyCombination of epidermal and mucus producing cells. Equal cystic and solid components, no pulmonary parenchymal invasion and absence of necrosis and mitotic activityMore areas of solid than cystic growth, with invasion of surrounding pulmonary parenchyma. Dominant component of squamoid and transitional cells. Presence of mitotic activity and necrosis.StainingBoth types are positive for keratin, CAM 5.2 and negative for S-100 protein, actin and chromogranin.MetastasisUncommonCommonTreatmentSurgerySurgery +/− Chemo and radiation Rx.
J.F. Durrani, None.