Reticular and Myxoid Non-keratinizing Nasopharyngeal Carcinoma: An Unusual Case Mimicking a Salivary Gland Carcinoma

Abstract

We present a case of non-keratinizing carcinoma of the nasopharynx (NK-NPC) with an unusual histopathological pattern. The neoplastic cells were arranged in anastomosing cords embedded in a stroma which contained a significant component of alcian blue-positive myxoid substance forming a reticular pattern. These histopathological features gave an initial impression of a salivary gland-type carcinoma. On immunohistochemistry the tumor cells were strongly and diffusely positive for cytokeratins (AE1-3 and 5/6) and p63 and there was strong and diffuse nuclear positivity for Epstein-Barr virusencoded small RNA on in situ hybridization. This case highlights the histomorphological variability of NK-NPC. Awareness of the histological spectrum of NK-NPC is important in clinical practice and this is not always adequately highlighted in currently used standard textbooks of Head and Neck Pathology.

Low-grade nasopharyngeal papillary adenocarcinoma: a case report and review of the literature

“… 14 Some studies have detected low-expression levels of EBV markers in the NPAC tissue. 2 , 15 Therefore, the relationship between NPACs and EBV is still uncertain. Further examination is still needed because of the extreme rarity of this tumor.…”

Nasopharyngeal carcinoma: A review

“…5). 100 Although the (reactive) lymphoplasmacytic infiltrate may vary, the presence of a desmoplastic-type stromal response to a NK-NPC is rarely encountered (Fig. 6).…”

EBV-Associated Non-keratinizing Nasopharyngeal Carcinoma with Prominent Spindled Cell and Whorling Patterns: A Previously Unreported Histological Variant in a Patient Presenting with Dermatomyositis

“…The neoplastic cells showed strong nuclear positivity for EBV (EBER-CISH), which also highlighted the nodular whorling architecture (d) cells, pleomorphic (Reed-Sternberg like) cells, desmoplastic stroma, a granulomatous component, eosinophilic cytoplasmic globules, associated abundant eosinophilic or neutrophilic granulocytes, amyloid, and prominent papillarity [1]. Very rarely, a reticular myxoid pattern or adenomatous differentiation may be encountered [2].…”

“…These include tumors with spindle cells, clear cells, presence of bizarre (Reed-Sternberg-like) tumor cells, non-caseating granulomas, papillarity, with abundant eosinophils or neutrophils, a desmoplastic stromal reaction, amyloid and eosinophilic cytoplasmic globules [1]. Very rarely, NPC may display a cord-like, reticular arrangement of tumor cells associated with significant myxoid substances in the stroma [2]. Another very uncommon histological pattern in NPC is adenomatous/glandular differentiation [3].…”