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Somatostatin scan positive gastrinoma ocular metastasis
  1. KEIR E LEWIS,
  2. PAUL B ROGERS
  1. Department of Clinical Oncology
  2. Department of Ocular Oncology
  3. Department of Nuclear Medicine
  4. Department of Clinical Oncology, St Bartholomew’s Hospital, West Smithfield, London EC1A 7BE
  1. JOHN HUNGERFORD
  1. Department of Clinical Oncology
  2. Department of Ocular Oncology
  3. Department of Nuclear Medicine
  4. Department of Clinical Oncology, St Bartholomew’s Hospital, West Smithfield, London EC1A 7BE
  1. KEITH E BRITTON
  1. Department of Clinical Oncology
  2. Department of Ocular Oncology
  3. Department of Nuclear Medicine
  4. Department of Clinical Oncology, St Bartholomew’s Hospital, West Smithfield, London EC1A 7BE
  1. P NICHOLAS PLOWMAN
  1. Department of Clinical Oncology
  2. Department of Ocular Oncology
  3. Department of Nuclear Medicine
  4. Department of Clinical Oncology, St Bartholomew’s Hospital, West Smithfield, London EC1A 7BE
  1. Dr Plowman.

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Editor,—Symptomatic ocular metastases are uncommon despite the 4% prevalence in patients dying of all types of malignancy in postmortem series.1 We report a case of ocular metastasis from a gastrinoma, which was part of the Wermer’s syndrome (multiple endocrine neoplasia (MEN) type 1), diagnosed by indium labelled octreotide scanning.

CASE REPORT

A 57 year old man presented with a 1 week history of blurring in his peripheral vision in his right eye and severe loss of visual acuity, worse early morning. He had been diagnosed with MEN type 1, 8 years previously after two perforated jejunal ulcers (1978, 1990) led to a diagnosis of Zollinger–Ellison syndrome, and a hyperplastic parathyroid gland had been removed for hypercalcaemia (1990). His mother had MEN type 1.

Ophthalmic examination revealed 6/12 acuity in the right eye and 6/5 in the left. His anterior segments were unremarkable. His right fundus showed a solid amelanotic lesion about one disc diameter above the right disc. Ultrasonography demonstrated a base of 13 mm and a height of 8 mm. He also had bilateral inferior retinoschisis. One month later the tumour base measured 14.5 mm and the thickness measured 7.9 mm. The posterior edge now practically abutted the optic disc (Fig 1). There was subretinal fluid accumulation.

Figure 1

Retinal photograph showing amelanotic neuroendocrine tumour.

A liver ultrasound scan showed multiple lesions and a tumour biopsy was composed of small solid islands of polygonal cells with granular cytoplasm, diagnostic of metastatic neuroendocrine carcinoma (immunostaining positive for chromogranin, neuron specific enolase, and NCAM, negative for S-100 and HMB45 (melanoma markers)). His urinary 5HIAA was marginally raised at 133 μmol/24 hours (normal up to 75), and a fasting intestinal peptide screen, showed a highly elevated gastrin level (on omeprazole 40 mg per day) of 343 pmol/l (normal range 0–40 pmol/l) but normal levels of other polypeptides.

No primary tumour or further metastases were seen using body computed tomograph and magnetic resonance imaging scans and the I-123 MIBG scan (meta-iodobenzyl guanidine) was also negative. An indium (In-111) labelled octreotide scan at 1 and 4 hours +SPET showed focal areas of increased uptake in the right orbit (Fig 2), the nasal region, mediastinum, multiple sites in the liver, and possibly other abdomen sites. However, a positive octreotide scan is not exclusively seen with neuroendocrine tumours, since other tissues have somatostatin receptors. These include high grade lymphoma, some small cell lung cancers, occasional tumours of the breast, and in chronic inflammatory conditions where there is T cell activation including endocrine ophthalmopathy with orbital involvement. Thus, although an absolute positive diagnosis of metastatic gastrinoma cannot be made definitively in the absence of histology, in the context of this clinical case it is highly probable that the choroidal tumour is due to ocular metastasis from gastrinoma.

Figure 2

Image from indium (In-111) labelled octreotide scan taken 4 hours after injection showing very avid focal uptake in the right orbit.

COMMENT

Gastrinoma may occur sporadically or as part of multiple endocrine neoplasia. MEN type 1 is a rare disorder, usually inherited in an autosomal dominant fashion with high penetrance which affects multiple endocrine glands (hyperparathyroid hyperplasia in 80–90%, pancreatic islet tumours in 50%, and pituitary adenomas in 40–50%).2

Ocular metastasis from gastrinoma has not previously been reported, although it has been reported in other neuroendocrine tumours—for example, carcinoid.3 Multiple or metastatic gastrinomas (especially if actively secreting) are best localised by a new radioisotope scan using radioactively labelled somatostatin analogues.4 5 Somatostatin is a peptide elaborated by the delta cells of the islets of Langerhans and the hypothalamus. It inhibits the secretion of gastrin by gastric mucosa and many other hormones such as insulin, thyrotropin, and corticotropin. Somatostatin receptors are found on neuroendocrine tumours (80% of gastrinomas) and indium labelled octreotide visualises all somatostatin receptor positive gastrinomas.4 5 Our scans revealed somatostatin avid liver metastases. Interestingly, the scan also very clearly confirmed the ocular/orbital disease. Orbital radiotherapy and chemotherapy were recommended.6

References

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