Syndrome of inappropriate antidiuretic hormone secretion in a case of olfactory neuroblastoma without anti-diuretic hormone immunoreactivity: A case report and review of the literature

Ectopic Olfactory Neuroblastoma: Systematic Review of a Rare Clinical Entity among Sinonasal Tumors

Objectives  Ectopic olfactory neuroblastoma is an uncommon manifestation of an already rare neoplasm. We aimed to systematically review the literature for cases of ectopic olfactory neuroblastoma to better characterize this rare disease entity and to present two new case reports. Methods  A search of the PubMed and Embase databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify English-language articles reporting cases of ectopic olfactory neuroblastoma, published from 1955 through November 2021. Results  Sixty-six cases of ectopic olfactory neuroblastoma were identified in 62 articles including the current review. Ectopic olfactory neuroblastoma arose in a wide age range (2-89 years) without significant sex predilection. It occurred most commonly in the ethmoid (25%), maxillary (25%), and sphenoid (16%) sinuses. Seventy-three percent of cases presented with low Hyams grade (I and II). The most common symptoms were nasal obstruction (32%) and epistaxis (32%). Paraneoplastic syndromes were observed in 27% of patients. The most common treatment was surgical resection followed by adjuvant radiotherapy. Overall, 76% of all patients were disease-free at the time of last follow-up. Locoregional recurrences and distant metastases were found in 19 and 5% of cases, respectively. Conclusion  This systematic review describes previously reported cases of ectopic olfactory neuroblastoma, a disease entity with poorly understood characteristics. Physicians should consider olfactory neuroblastoma in the differential diagnosis for sinonasal masses, as their ectopic presentation may present considerable diagnostic and therapeutic difficulties. Patients with olfactory neuroblastoma may benefit from long-term follow-up and routine endoscopic examinations for surveillance of ectopic recurrences.

The syndrome of inappropriate antidiuretic hormone associated with nasal and paranasal malignant tumors

PURPOSE

To investigate the clinical characteristics of the syndrome of inappropriate antidiuretic hormone (SIADH) associated with nasal and paranasal malignant tumors.

METHODS

Patients with locally advanced or recurrence/metastatic malignant tumors of the nasal and paranasal sinuses were included. The SIADH was diagnosed according to the diagnostic criteria. The clinical characteristics of SIADH patients were retrospectively analyzed.

RESULTS

Six patients (6/188, 3.2%) met the diagnostic criteria of SIADH, including four olfactory neuroblastoma (4/26, 15.4%), one neuroendocrine carcinoma (1/9, 11.1%), and one squamous cell carcinoma (1/63, 1.6%). Five patients (83.3%) had severe hyponatremia; however, the hyponatremia could be improved by fluid restriction or tolvaptan. Three patients' SIADH were recovered during the chemotherapy and the other three were recovered after the surgery.

CONCLUSION

The incidence of SIADH associated with nasal and paranasal malignant tumors is relatively more common in olfactory neuroblastoma and neuroendocrine carcinoma. The hyponatremia caused by SIADH may be corrected by fluid restriction or tolvaptan, and the SIADH may be recovered through anti-tumor therapy.

Functional Olfactory Neuroblastoma Inducing Symptomatic SIADH

Olfactory neuroblastoma (ONB) is a rare malignancy of the sinonasal cavity, originating from neuroepithelial olfactory cells. Olfactory neuroblastoma can be difficult to diagnose due to its anatomic position and variable symptomatic presentation, leading to diagnosis at a more advanced stage. Here, we present the case of a 35-year-old man with no previous medical history who had a bicycle accident secondary to syncope. He was found to be hyponatremic and suspected to have syndrome of inappropriate antidiuretic hormone secretion (SIADH). In the workup of SIADH, a brain magnetic resonance imaging revealed a mass in the left middle meatus. The lesion secreted inappropriate amounts of ADH, resulting in symptomatic paraneoplastic SIADH. This ultimately led to the early recognition and successful resection of this rare ONB. The patient has remained disease-free for over 5 years. This case is a fortunate example of a functional malignancy of the sinonasal tract that was discovered early and successfully treated as a result of symptomatic SIADH.

The V2 receptor antagonist tolvaptan counteracts proliferation and invasivity in human cancer cells

PURPOSE

Hyponatremia, the most frequent electrolyte alteration in clinical practice, has been associated with a worse prognosis in cancer patients. On the other hand, a better outcome has been related to serum sodium normalization. In vitro studies have shown that low extracellular sodium promotes cancer cells proliferation and invasiveness. Tolvaptan, a selective vasopressin receptor type 2 (V₂) antagonist, has been effectively used in the last decade for the treatment of hyponatremia secondary to the Syndrome of Inappropriate Antidiuresis. A few in vitro data suggested a direct role of tolvaptan in counteracting cancer progression, so far. The aim of this study was to evaluate the effect and the mechanism of action of tolvaptan in cell lines from different tumours [i.e. colon cancer (HCT-8), hepatocarcinoma (HepG2), neuroblastoma (SK-N-AS)].

METHODS AND RESULTS

First, we showed that these cell lines express the V₂ receptor. Tolvaptan significantly reduced cell proliferation with an IC₅₀ in the micromolar range. Accordingly, reduced levels of cAMP, of the catalytic α subunit of PKA, and a reduced pAKT/AKT ratio were observed. Tolvaptan effectively inhibited cell cycle progression, whereas it induced apoptotis. Furthermore, it reduced cell invasiveness. In particular, anchorage-independent growth and the activity of collagenases type IV were blunted in the three cell lines. Accordingly, tolvaptan counteracted the RhoA/ROCK1-2 pathway, which has a pivotal role in regulating cell movement.

CONCLUSIONS

Overall, these findings indicate that tolvaptan effectively inhibits tumour progression in vitro. Further studies should clarify whether the V₂ receptor might be considered a possible target in anti-cancer strategies in the future.

Exclusively endoscopic surgical resection of esthesioneuroblastoma: A systematic review

Background

Historically sinonasal malignancies were always addressed via open craniofacial surgery for an oncologic resection. Increasingly esthesioneuroblastomas are excised using an exclusively endoscopic approach, however, the rarity of this disease limits the availability of long‐term and large scale outcomes data.

Objective

The primary objective is to evaluate the treatment modalities used and the overall survival of patients with esthesioneuroblastoma managed with exclusively endoscopic surgery.

Methods

In accordance with PRISMA guidelines, PubMed was queried to identify studies describing outcomes associated with endoscopic management of esthesioneuroblastomas.

Results

Forty‐four out of 2462 articles met inclusion criteria, totaling 399 patients with esthesioneuroblastoma treated with an exclusively endoscopic approach. Seventy‐two patients (18.0%) received adjuvant chemotherapy and 331 patients (83.0%) received postoperative radiation therapy. The average age was 50.6 years old (range 6–83). Of the 399 patients, 57 (16.6%) were Kadish stage A, 121 (35.2%) were Kadish stage B, 145 (42.2%) were Kadish stage C, and 21 (6.1%) were Kadish stage D. Pooled analysis demonstrated that 66.0% of patients had Hyams histologic Grade Ⅰ or Ⅱ, while 34.0% of patients had Grade Ⅲ or Ⅳ disease. Negative surgical margins were achieved in 86.9% of patients, and recurrence was identified in 10.3% of patients. Of those with 5‐year follow‐up, reported overall survival was 91.1%.

Conclusion

Exclusively endoscopic surgery for esthesioneuroblastoma is performed for a wide range of disease stages and grades, and the majority of these patients are also treated with adjuvant chemotherapy or radiation therapy. Reported overall recurrence rate is 10.3% and 5‐year survival is 91.1%.

Molecular Biomarkers in Sinonasal Cancers: New Frontiers in Diagnosis and Treatment

Purpose of Review

Sinonasal tumors are rare and heterogeneous diseases which pose challenges in diagnosis and treatment. Despite significant progress made in surgical, oncological, and radiotherapy fields, their prognosis still remains poor. Therefore, alternative strategies should be studied in order to refine diagnosis and improve patient care.

Recent Findings

In recent years, in-depth molecular studies have identified new biological markers, such as genetic abnormalities and epigenetic variations, which have allowed to refine diagnosis and predict prognosis. As a consequence, new histological entities have been described and specific subgroup stratifications within the well-known histotypes have been made possible. These discoveries have expanded indications for immunotherapy and targeted therapies in order to reduce tumor spread, thus representing a valuable implementation of standard treatments.

Summary

Recent findings in molecular biology have paved the way for better understanding and managing such rare and aggressive tumors. Although further efforts need to be made in this direction, expectations are promising.

A sellar neuroblastoma showing rapid growth and causing syndrome of inappropriate secretion of antidiuretic hormone: A case report

Background:

Sellar neuroblastoma is a very rare entity. We report a rare case of arginine vasopressin (AVP)- producing sellar neuroblastoma presumed to have originated from the lower part of sellar turcica, which grew very rapidly.

Case Description:

A 33-year-old woman was found to have a sellar lesion with a diameter of 18 mm invading into the bilateral cavernous sinus on magnetic resonance imaging (MRI) performed for dizziness. Six years later, when she visited the clinic due to bilateral visual disturbance, MRI showed a rapid growth of the tumor, with a maximal diameter of 56 mm at the current state, strongly compressing the optic nerve and chiasm. Transsphenoidal decompression of the optic chiasm revealed an intact pituitary gland on the top of the tumor. The tumor was composed of neoplastic cells that were immunohistochemically positive for neuronal markers and arginine vasopressin (AVP), but negative for all anterior pituitary hormones, glial fibrillary acidic protein, or thyroid transcription factor-1; these findings were suggestive of sellar neuroblastoma. She underwent 50-Gy radiation therapy, which has controlled the growth for the past 3 years.

Conclusion:

Awareness of rare sellar neuroblastomas will allow the accumulation of clinicopathologic information that may facilitate the understanding of their origin, clinical features, neuroimaging characteristics, and pertinent adjuvant treatment.