California Tumor Tissue Registry

Case of the Month

February, 2003

“A 65 Year-old Male with Wheezing and a Productive Cough”

A 65 year old male with a five month history of asthma, became febrile and developed shaking chills. His wheezing increased and was only minimally responsive to metered dose inhalers. After five days, he developed a productive cough associated with brownish, blood-tinged sputum. A chest x-ray showed left sided atelectasis. A bronchoscopy found an occlusive, exophytic mass in the left mainstem bronchus, approximately 3 cm from the carina. A CT scan further delineated it as being 1.2 cm in greatest diameter (Fig. 1). Adenopathy was not seen.

A left upper lobectomy was performed, which includeda segmental resection of the left mainstem bronchus, and lymph node dissections of the paraortic and left inferior pulmonary ligament regions. Grossly, the tumor was polypoid, gray-tan,andfirmly attached to the wall of the bronchus. It partially obstructed the lumen, and was associated with copious white mucus.

The tumor was microscopically shown to arise from the bronchial mucosa, and to beconfined to the luminal side of the cartilage (Figs. 2,3). No invasion was seen. The tumor showed both solid and papillary growth patterns (Fig. 4), and consisted of an admixture of glandular and squamous elements (Fig. 5). Many cells showed mucin production and marked positively for PAS and mucicarmine stains (Fig. 6). The squamous-like regions consisted of epithelioid cells with eosinophilic foamy cytoplasm and plump, vesicular nuclei (Fig 7). There were also several foci of mixed inflammation consisting of lymphocytes, neutrophils, and plasma cells. Mitoses were only rarely encountered.

Diagnosis: “Pulmonary mucoepidermoid carcinoma”

Jacqueline Benjamin, M.D., and Donald R. Chase, M.D., Loma Linda

UniversityMedicalCenter, Loma Linda,California

Mucoepidermoid carcinoma is a rare pulmonary malignancy, comprising 0.16 to 2% of all primary lung cancers. Since it was first described in 1952 by Smetana et. al. as a subtype of bronchial adenoma, it has been shown to have no gender predilection, and to occur in people of any age. Approximately 67% arise in patients who are 45 to 70 years old, while 14% occur in children. Although these tumors generally arise de novo, an association with immunosuppression has been reported after an allogeneic bone marrow transplant.

Patients with the disease usually present with cough, wheezing, hemoptysis, dyspnea, weight loss, and/or general malaise. Cases of post-obstructive pneumonia have been described. To date, there has been no association with cigarette smoking.

The tumor most commonly is found to arise from the submucosal glands of central bronchi, preferentially involving the right side. It may also arise from the trachea. It may have either low or high grade histologic characteristics. The low grade variant has sheets of monomorphic cells with well-formed mucus glands and virtually no mitotic figures. The high grade variant, however, shows numerous atypical, pleomorphic cells with numerous mitoses, and focal necrosis. Mucous-forming glands and goblet cells are rare in high grade tumors.

Although low grade histology is generally associated with a much better prognosis, there have been reports of metastasis in Grade I tumors (Ozlu et al and Dowling et al), including distant spread to skin (Metcal et al). Despite these case reports, mucoepidermoid tumors of the tracheal-bronchial tree are usually low grade, and generally follow a benign clinical course, being adequately treated by total surgical extirpation.

Suggested Reading:

1)Chen F, Tatsumi A, and Miyamato Y. Successful treatment of mucoepidermoid carcinoma of the carina. Ann Thoracic Surg. 71:366-368, 2001.

2)Guillou L, De Luze, P, etal. Papillary variant of low-grade mucoepidermoid carcinoma – an unusual bronchial neoplasm. Clin Pathol. 101:269-274, 1994.

3)Klacsmann PG, Olson, JL., and Eggleston JC. Mucoepidermoid carcinoma of the bronchus. An electron microscopic study of the low grade and the high grade variants. Cancer. 43:1720-1733, 1979.

4)Leonardi KH, Jung-Legg Y, etal. Tracheobronchial mucoepidermoid carcinoma. Clinicopathological features and results of treatment. J Thoracic Cardiovasc Surg. 76(4):431-438, 1978.

5)Sanchez, J, Serrano J, et al. Bronchial mucoepidermoid carcinoma after allogeneic bone marrow transplantation. J Clin Path. 50:969-970, 1997.

6)Turnbull AD, Huvos AG, et al. Mucoepidermoid tumors of bronchial glands. Cancer. 28:539-544, 1971.

7)Wolf KM, Mehta D, and Claypool WD. Mucoepidermoid carcinoma of the lung with intracranial metastases. Chest. 94(2):435-437, 1988.

CTTR’s Case of the MonthFebruary, 20031