Melanotic oncocytic metaplasia of the nasopharynx: a case report with a focus on immunohistochemical analyses and literature review.

Melanotic oncocytic metaplasia (MOM) of the nasopharynx is an extremely rare lesion, with only 21 cases reported in English literature to date. MOM typically occurs near the Eustachian tube opening in Asian men in their 60 s to 70 s. Here, we present a case of MOM in a 57-year-old Japanese man who is a heavy smoker. The patient did not have complaints; MOM was diagnosed incidentally as 4 flat elevated lesions with brown to black discoloration, ranging from 2 to 3 mm in maximal diameter, were found in the right torus tubarius. On suspecting melanoma, the largest lesion was biopsied. Microscopic examination identified both oncocytic metaplasia and melanin pigmentation of the epithelium in the same gland. Upon immunohistochemical examination, melanocytes displayed reactivity for 3 out of 4 melanocytic markers; immunopositivity for S-100 protein, Melan-A, and MITF and immunonegativity for HMB-45 was observed. Normal melanocytes in the nearby surface respiratory epithelium displayed the same pattern of immunoreactivity. Immunopositivity for S-100 protein and immunonegativity for HMB-45 have been previously reported in MOM. Reduction of stimulation of melanocytes in a longstanding lesion like MOM may explain the immunonegativity for HMB-45. S-100 protein, in conjunction with more specific marker for melanocytes, Melan-A or MITF, could prove the definite presence of melanocytes in this case of MOM. As it has been shown by previous reports that MOM pursues a benign course, it will be sufficient to follow up the patients regularly for the remaining 3 lesions.

Ewing's sarcoma family of tumors of the maxillary sinus: a case report of multidisciplinary examination enabling prompt diagnosis.

There have been approximately 10 reports in English literature of cases of Ewing's sarcoma family of tumors (EFT) arising in the maxillary sinus. In this location, some tumors mimic EFT, and are more frequently encountered. Herein, we present an additional case of an EFT originating in the maxillary sinus. The patient was a 15-year-old boy complaining of a non-tender swelling of the left cheek. Laboratory tests showed no abnormalities. Computed tomography and magnetic resonance imaging revealed a mass centered in the maxillary sinus with degeneration of the surrounding bones. Pathological examination along with flow cytometry and G-banding enabled the prompt diagnosis of EFT with the EWS/FLI1 fusion gene. The patient is planned to undergo chemotherapy. An origin in the head and neck and the presence of the typical EWS/FLI1, in conjunction with an opportunity for immediate treatment, may predict a relatively better prognosis for EFT in our case.

A rare Japanese case with a NUT midline carcinoma in the nasal cavity: a case report with immunohistochemical and genetic analyses.

BACKGROUND: NUT (nuclear protein in testis) midline carcinoma (NMC) is a recently described aggressive malignancy that is genetically defined by rearrangements of the NUT locus at 15q14. In approximately two-thirds of cases, the characteristic t(15;19) results in the fusion oncogene BRD4-NUT. Only 10 sinonasal NMCs have been documented, none of which were Japanese cases. CASE PRESENTATION: An 18-year-old woman was admitted because of a rapidly progressing tumor in the nasal cavity. A biopsy revealed an undifferentiated neoplasm without squamous differentiation. The tumor cells had round to oval nuclei with vesicular chromatin, prominent nucleoli, and scant cytoplasm. Immunohistochemical staining demonstrated a strong positivity for vimentin and NUT, with focal CD138 and only spotty EMA and cytokeratin AE1/AE3 staining. Cytogenetic and fluorescence in situ hybridization analyses revealed a t(15;19) and BRD4-NUT gene rearrangement. Direct sequencing identified the in-frame fusion of exon11 of BRD4 with exon2 of NUT. The patient was transferred to another hospital for chemoradiotherapy. CONCLUSION: We herein describe the first Japanese case with an NMC of the sinonasal cavity, providing detailed and unambiguous cyto- and molecular genetic information on BRD4-NUT-rearrangement. The accumulation of cases with well-documented genetic data should provide clues to the treatment of this tumor entity.