Malignancies arising in oncocytic schneiderian papillomas: A report of 2 cases and review of the literature

Archives of Pathology & Laboratory Medicine, Oct 2001 by Maitra, Anirban, Baskin, Leland B, Lee, Edward L

A Report of 2 Cases and Review of the Literature

Oncocytic schneiderian papillomas (OSPs) are uncommon benign neoplasms that arise from the sinonasal schneiderian epithelium. Malignancies arising in OSPs are rare, and, to our knowledge, only 14 such instances have been reported in the medical literature. We report 2 additional cases-a small cell carcinoma and a sinonasal undifferentiated carcinoma arising in OSPs and presenting synchronously with the benign neoplasm. The potential for malignant transformation in OSPs is small, but warrants that these papillomas be completely excised to exclude a coexisting carcinoma.

(Arch Pathol Lab Med. 2001;125:1365-1367)

The schneiderian epithelium, which lines the nasal and paranasal sinuses, gives rise to 3 histologically distinct papillomas: septal, inverted, and oncocytic schneiderian papillomas (OSPs).1,2 The OSPs are the rarest of the 3 subtypes, accounting for only 3% of all sinonasal papillomas.2 Sinonasal papillomas have a small but distinct risk of malignant transformation, which occurs virtually always in the inverted subtype.2-6 Malignancies arising in OSPs are rare (Table 1), with invasive squamous cell carcinoma being the most frequently reported tumor.2,7-10 We report 2 additional cases of malignancies associated with OSPs, including the first case of a small cell carcinoma (SCC) and the third case of a sinonasal undifferentiated carcinoma (SNUC).

REPORT OF CASES

Case I

A 71-year-old white man presented to the Dallas Veterans Affairs Medical Center with complaints of left nostril fullness for 2 months. On examination he had proptosis on the left side. A computed tomographic scan of the head revealed a large maxillary sinus mass eroding into the orbital floor and into the nasal cavity. A left medial maxillectomy with removal of the mass was performed. The patient presented 2 months after surgery with adenopathy on the left side of the neck, which showed metastatic SCC on fine needle aspiration. Scattered foci of metastatic SCC were seen in the bone marrow aspirate. Despite chemotherapy, he developed progressive disease involving his liver, spine, and brain and died 9 months after the first biopsy. No postmortem examination was performed.

Case 2

A 64-year-old African American man presented to the Dallas Veterans Affairs Medical Center with a 4-month history of epistaxis and nasal airway obstruction. Examination revealed a polypoid mass within the left nasal cavity replacing the left middle turbinate. A computed tomographic scan showed a 3-cm mass in the left nasal cavity, eroding the middle turbinate and abutting the septum. Biopsy of the mass followed by left medial maxillectomy and modified neck dissection was performed. The patient received adjuvant radiotherapy. The patient is in complete clinical remission 14 months after surgery.

PATHOLOGIC FINDINGS

Case 1

The OSP comprised a minor component of the specimen. It was composed of multilayered columnar epithelium that showed both exophytic and inverted growth patterns. The cytoplasm was deeply eosinophilic and granular. Numerous mucinous microcysts, some with neutrophils within them, were present in the epithelium. Cytologic atypia or mitotic activity was not seen. The bulk of the specimen, however, was composed of an SCC, with the neoplastic cells having irregular hyperchromatic nuclei, inconspicuous nucleoli, abundant mitotic activity, and single cell necrosis. Nuclear "crush" artifact and molding were present focally. The SCC was intimately associated with the OSP, and in some areas, the epithelium of the OSP was undermined by nests of SCC (Figure, a and b). Immunohistochemical analysis demonstrated diffuse reactivity for cytokeratin AE1/AE3 in the OSP and focal reactivity in the SCC. Focal neuron-specific enolase (NSE) and chromogranin expression was restricted to the SCC, whereas phosphotungstic acid and Luxol fast blue, which stain mitochondria, were positive in the OSP Ultrastructural examination showed neoplastic cells with prominent nuclear molding and occasional dense core neurosecretory granules, consistent with an SCC.

Case 2

The initial biopsy specimen showed a tiny focus of classic OSP, with most of the epithelium being composed of markedly dysplastic cells that merged into areas of frank carcinoma in situ. The maxillectomy specimen showed more classic areas of OSP, in conjunction with an invasive SNUC. The SNUC was characterized by sheets of medium-sized polygonal cells with round to oval nuclei and conspicuous nucleoli. Mitotic figures and necrosis were abundant. There was histologic continuity from benign oncocytic epithelium to areas of dysplasia and carcinoma in situ; the latter were intimately associated with intramucosal nests of SNUC (Figure, c and d). Immunohistochemical analysis of the SNUC (see Table 2 for antibody specifications) showed reactivity restricted to cytokeratin CAM 5.2, with lack of expression of cytokeratin AE1/AE3, synaptophysin, chromogranin, NSE, HMB-45, S100, leukocyte common antigen, CD20, and CD3.