Autoimmune retinopathy associated with carcinoid tumour of the small bowel

Neurological autoimmunity in patients with non-pulmonary neuroendocrine neoplasms: clinical manifestations and neural autoantibody profiles

BACKGROUND AND PURPOSE

Paraneoplastic neurological autoimmunity is well described with small-cell lung cancer, but information is limited for other neuroendocrine neoplasms (NENs).

METHODS

Adult patients with histopathologically confirmed non-pulmonary NENs, neurological autoimmunity within 5 years of NEN diagnosis, and neural antibody testing performed at the Mayo Clinic Neuroimmunology Laboratory (January 2008 to March 2023) were retrospectively identified. Control sera were available from patients with NENs without neurological autoimmunity (116).

RESULTS

Thirty-four patients were identified (median age 68 years, range 31-87). The most common primary tumor sites were pancreas (nine), skin (Merkel cell, eight), small bowel/duodenum (seven), and unknown (seven). Five patients received immune checkpoint inhibitor (ICI) therapy before symptom onset; symptoms preceded cancer diagnosis in 62.1% of non-ICI-treated patients. The most frequent neurological phenotypes (non-ICI-treated) were movement disorders (12; cerebellar ataxia in 10), dysautonomia (six), peripheral neuropathy (eight), encephalitis (four), and neuromuscular junction disorders (four). Neural antibodies were detected in 55.9% of patients studied (most common specificities: P/Q-type voltage-gated calcium channel [seven], muscle-type acetylcholine receptor [three], anti-neuronal nuclear antibody type 1 [three], and neuronal intermediate filaments [two]), but in only 6.9% of controls. Amongst patients receiving cancer or immunosuppressive therapy, 51.6% had partial or complete recovery. Outcomes were unfavorable in 48.3% (non-ICI-treated) and neural autoantibody positivity was associated with poor neurological outcome.

DISCUSSION

Neurological autoimmunity associated with non-pulmonary NENs is often multifocal and can be treatment responsive, underscoring the importance of rapid recognition and early treatment.

Cancer-associated retinopathy preceding the diagnosis of a pulmonary carcinoid tumour

Cancer-associated retinopathy (CAR) belongs to the paraneoplastic retinopathy syndromes and manifests itself by rapidly progressive vision loss, scotoma and photopsia. We herein reported the case of a 77-year-old woman without a cancer history who presents typical CAR symptoms. A complete workup followed by lung biopsy enabled the detection of a pulmonary carcinoid tumour. Treatment of oral cortisone was then initiated with dramatic improvements in the symptoms.

Cancer-associated retinopathy in ampullary pancreatic cancer

A 64-year-old woman presented with bilateral visual loss with shimmering photopsias as the only clinical manifestation of an occult pancreatic ampullary adenocarcinoma causing duct dilatation. Abnormal electroretinograms led to suspicion of cancer-associated retinopathy (CAR), and CT of the abdomen showed an underlying pancreatic malignancy, detected with subclinical liver function tests following diagnosis of CAR. Biopsy showed a T2N0M0 ampullary adenocarcinoma. The patient was managed with Whipple's procedure and adjuvant chemotherapy and has made a good recovery with no progression of her retinopathy. To our knowledge, this is one of the first descriptions of CAR in the context of pancreatic malignancy. It is atypical in its asymmetric presentation and favourable patient outcome. CAR is an important diagnosis to make, as ocular manifestations can be the only indication of an occult malignancy, resulting in a swifter diagnosis and potentially life-saving early intervention.

Cancer-associated retinopathy as the leading symptom in colon cancer

Cancer-associated retinopathy (CAR) is a rare paraneoplastic visual syndrome. Its early detection may lead to the diagnosis of the causative malignancy. As many different types of malignancies are known to be associated with CAR, it is important that clinicians are aware of the phenomenon of CAR.