Lysosomal inclusions in gastric parietal cells in mucolipidosis type IV - A novel cause of achlorhydria and hypergastrinemia

Mucolipidosis type IV (ML-IV) is an autosomal recessive lysosomal storage disease that causes severe neurologic abnormalities. The brain disease is characterized by pigmented cytoplasmic granules in neurons and accumulation of lamellated membrane structures in lysosomes. The gastrointestinal disease in ML-IV was not previously recognized. Clinical examination of 20 patients with ML-IV (age range, 2-23 years) at the National Institutes of Health showed hypergastrinemia and constitutive achlorhydria. Endoscopic biopsy specimens, from the gastric fundus, body, and antrum and from the duodenum of four such patients (ages 4, 6, 7, and 22 years) were evaluated histologically and by electron microscopy. Histologically, all gastric fundus and body biopsy specimens showed parietal cells in normal numbers. However, a striking cytoplasmic vacuolization of parietal cells was seen on hematoxylin and eosin stain. Electron microscopy showed the parietal cells to be markedly distended by large lysosomes containing lamellar, concentric, and cystic membranous inclusions. Additionally, chronic atrophic gastritis and enterochromaffin-like (ECL) cell hyperplasia were observed. Foveolar and chief cells in stomach and duodenum biopsy specimens were normal. We conclude that the cytoplasmic lysosomal inclusions in gastric parietal cells is a unique histologic feature of gastric biopsy in ML-IV.