Schmitt, Alessandra

Inverted sinonasal papilloma (ISP) and respiratory epithelial adenomatoid hamartoma (REAH) are sinonasal lesions with overlapping clinical, radiographic, and histologic features, making accurate diagnosis challenging. ISP is a benign but aggressive tumor with a propensity for local destruction, recurrence, and malignant transformation, whereas REAH is a hamartomatous lesion often arising in the olfactory cleft. We present four patients with lesions initially suspected to be ISP based on intraoperative frozen section but ultimately diagnosed as REAH on permanent pathology. All patients had polypoid sinonasal masses, frequently involving or adjacent to the olfactory cleft. Intraoperative frozen sections were often inconclusive or favored ISP, reflecting the difficulty of distinguishing these entities. Histologic analysis revealed that epithelial thickness served as a key morphologic feature differentiating ISP from REAH, with REAH exhibiting ciliated glandular proliferation and ISP characterized by hyperplastic epithelium with features of columnar and squamous differentiation. These patients underscore the diagnostic pitfalls of small biopsies and frozen sections, and highlight the importance of permanent specimens and collaboration with experienced pathologists. Accurate differentiation is critical, as management strategies differ substantially: ISP requires aggressive resection and long-term surveillance, while REAH may be treated with limited excision and minimal follow-up.

Rationale: Immunoglobulin (Ig) G4–related disease (IgG4-RD) reportedly has a strong relationship with adult-onset asthma and periocular xanthogranuloma (AAPOX) and may be linked to sclerosing mucoepidermoid carcinoma (MEC). We present a rare case of IgG4-RD and AAPOX occurring in a patient with resected eosinophilic or oncocytic MEC. Patient concerns: A 52-year-old woman was referred to our rheumatology clinic in 2020 to be evaluated for suspected IgG4-RD. Diagnoses: The patient had diagnoses of periorbital xanthelasmas, worsening glucocorticoid-dependent chronic rhinosinusitis and adult-onset asthma, and cervical lymphadenopathy persisting 2 years after resection of a low-grade MEC of a minor salivary gland. Interventions: Because the patient’s symptomatic relief was glucocorticoid dependent, IgG4-RD was suspected, and she was referred to our medical center. Her amylase and lipase levels were elevated. Serum IgG4 levels were initially within normal limits, but IgG4-RD was diagnosed because of the presence of lymphadenopathy and evidence of pancreatitis, which was shown on positron emission tomography/computed tomography. Furthermore, the IgG4 levels later increased without explanation. After the patient began combination therapy with a glucocorticoid (prednisone) and methotrexate, her symptoms improved but recurred when the daily oral glucocorticoid dosage decreased below 10 mg. An excisional biopsy of her right submandibular gland in 2021 yielded results consistent with IgG4-RD. In addition, AAPOX was diagnosed, given the presence of periocular edema and plaques, adult-onset asthma, and rhinosinusitis. Outcome: The patient was carcinoma free at last follow-up and was receiving medication to treat the other conditions. Lessons: The diagnosis of these 3 concomitant, uncommon entities required approximately 7 years of medical investigations. Clinicians should know that IgG4-RD, AAPOX, and MEC may occur together.