Adrenocorticotropic Hormone-Dependent Cushing Syndrome Caused by an Olfactory Neuroblastoma

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.

An olfactory neuroblastoma presenting as posterior reversible leukoencephalopathy syndrome

Olfactory neuroblastomas are rare malignancies of the nasal and sinus cavities. They have been associated with paraneoplastic syndromes due to secretion of adrenocorticotropin hormone (ACTH) or antidiuretic hormone. These associated paraneoplastic syndromes can present with a wide variety of symptoms that can make diagnosis of the underlying tumor difficult. Here we present the case of a 23-year-old woman who had a seizure due to the development of posterior reversible leukoencephalopathy syndrome because of secondary hypertension due to Cushing's syndrome, which was in turn found to be due to ectopic ACTH production from a metastatic olfactory neuroblastoma.

A Rare Case of Ectopic Adrenocorticotropic Hormone Syndrome with Recurrent Olfactory Neuroblastoma

A 40-year-old woman who had a history of recurrent olfactory neuroblastoma presented with full moon face, central obesity, buffalo hump, impaired glucose tolerance and bilateral cervical lymph node swelling. Laboratory tests showed morbidly elevated levels of adrenocorticotropic hormone (ACTH) and cortisol, which were not suppressed by high-dose (8 mg) dexamethasone. Biopsies of the enlarged cervical lymph nodes revealed ACTH-positive metastatic olfactory neuroblastoma, and ectopic ACTH syndrome was diagnosed. Metyrapone was used to suppress cortisol production and resulted in decreased levels of ACTH and cortisol. Bilateral cervical tumor resection further reduced the ACTH and cortisol levels, accompanied by a reduction in the metyrapone dosage. Cushing's syndrome was alleviated through ACTH-producing tumor removal.

Unusual ectopic ACTH syndrome in a patient with orbital neuroendocrine tumor, resulted false-positive outcome of BIPSS:a case report

BACKGROUND

Cushing's syndrome has been described as a complex endocrine disorder characterized with high cortisol concentration. Correct and early diagnosis of Cushing's syndrome is challenging. According to the latest guideline, bilateral inferior petrosal sinus sampling (BIPSS) is considered to be the gold standard for the differential diagnosis. However, in some unusual cases, this method may be false positive. Here, we presented a rare case of orbital neuroendocrine tumor secreting adrenocorticotrophic hormone with false positive inferior petrosal sinus sampling.

CASE PRESENTATION

A 48-year-old woman was admitted to West China Hospital of Sichuan University, presenting with fatigue, whole body edema for 1 year, alopecia and skin pigmentation for 5 months. Hormonal profiles including plasma cortisol and adrenocorticotrophic hormone (ACTH) measurements and low-dose dexamethasone inhibition test suggested that the patient had Cushing's syndrome. However, during tumor location phase, the results of high-dose dexamethasone inhibition test (HDDST) contradicted desmopressin (DDAVP) stimulation test. Thus, BIPSS was employed, and its results indicated a pituitary origin. Interestingly, MRI of sellar region showed an innocent pituitary but caught a serendipitous lesion in the lateral rectus muscle of left eye, which was later proved to be an orbital neuroendocrine tumor secreting ACTH by pathological and immunohistochemical results. ACTH level of the patients was < 0.1 ng/L and cortisol level was 51.61 nmol/L 1 week after surgery. At 24 months follow-up, the patient appeared stable with no complaints nor any symptoms of Cushing's syndrome, including moon face, purple striate and central obesity. The patient's life quality also improved significantly.

CONCLUSION

We reported a rare case of endogenous Cushing's syndrome due to ectopic ACTH secreting from an orbital neuroendocrine tumor. This unique case of orbital EAS suggests that orbital venous blood backflow, owning to abnormal anatomic structures, may possibly lead to false positive BIPSS results.

Adrenocorticotropic Hormone-Secreting Esthesioneuroblastoma with Ectopic Cushing's Syndrome

Esthesioneuroblastoma as a source of ectopic Cushing's syndrome is rare, and to the best of our knowledge, only 20 cases have been reported worldwide. A 46-year-old healthy man visited a local clinic for general weakness and hyposmia, and underwent examination with serial endocrinological workup and brain imaging. ⁶⁸Gallium-DOTA-TOC positron emission tomography scan was helpful where diagnosis of sellar MRI and inferior petrosal sinus sampling were discordant. Combined transcranial and endoscopic endonasal approach surgery was performed, and a diagnosis of esthesioneuroblastoma was given.