PMC8203267_01
Case 1. (A) Grossly, a mucinous cystic lesion maximally measured 72 mm, while in this figure a cut surface of the cystic and demarcated lesion measuring 30 mm is shown (arrow). The mural nodule is not included. (B) Nuclear stratification and anisonucleosis are observed (H&E). (C) The neoplastic epitheliums are positive for MUC5AC, and (D) focal positive for MUC6. (E) Hyaline globules (HGs) are clustered. HGs are round and acidophilic in appearance and perinuclear in location (H&E). (F) With Masson's trichrome, the HGs show bright red staining with fuchsinophilia (Masson's trichrome). Immunohistochemically, no HGs were positive for MUC6 (G), ubiquitin (H), 1-antitrypsin (I), and cleaved caspase-3 (J).
IMCRJ-14-393-g0001.jpg
PMC8203267_01_IMCRJ-14-393-g0001.jpg
f0001
Grossly, a mucinous cystic lesion measured 72 mm, and a 10 mm-sized mural nodule was attached (Figure 1A). There were nuclear pleomorphism, increased mitosis and stratification of the nuclei, indicating a malignant potential (Figure 1B). The surrounding non-neoplastic pancreas revealed no significant changes. The tumor cells expressed gastric-type mucin immunohistochemically: mucin 1 (MUC1)-, MUC2-, MUC5AC+ (Figure 1C), and MUC6 focally + (Figure 1D). Characteristically, intracytoplasmic eosinophilic hyaline globules (HGs) were multifocally clustered (Figure 1E). With Masson's trichrome, the HGs showed bright red staining with fuchsinophilia (Figure 1F). Immunohistochemically, the HGs were negative for MUC5AC, MUC6 (Figure 1G), p53, ubiquitin (Figure 1H), 1-antitrypsin (Figure 1I), and cleaved caspase-3 (Figure 1J).
PMC8203267_02
Case 2. (A) Grossly, a mucinous cystic and demarcated lesion, 45 mm in maximal diameter, is located in the pancreatic parenchyma, while in this figure a cystic and demarcated lesion measuring 25 mm is demonstrated (arrow). (B) HGs are clustered (H&E). The neoplastic cells are positive for MUC5AC (C) and MUC6 (D). Immunohistochemically, the HGs were negative for MUC6 (E; arrowheads), ubiquitin (F; arrowheads), 1-antitrypsin (G; arrowheads), and cleaved caspase-3 (H; arrowheads).
IMCRJ-14-393-g0002.jpg
PMC8203267_02_IMCRJ-14-393-g0002.jpg
f0002
Grossly, a mucinous lesion, 45 mm in size, was demarcated and encapsulated in the pancreatic parenchyma (Figure 2A). Intracytoplasmic HGs (thanatosomes) were multifocally clustered in the supranuclear cytoplasm of the adenoma cells (Figure 2B). Immunohistochemically, gastric-type mucin was observed [MUC1-, MUC2-, MUC5AC+ (Figure 2c), and MUC6+ (Figure 2D)]. The HGs were negative for MUC5AC, MUC6 (Figure 2E), p53, ubiquitin (Figure 2F), 1-antitrypsin (Figure 2G), and cleaved caspase-3 (Figure 2H).
Ultrastructural findings of the HGs in IPMN. (A-C) Ultrastructural findings of the HGs in Case1. The neoplastic cells are rich in mucin production. In addition to clustered electron-dense mucin granules, large-sized and globular electron-dense (osmiophilic) inclusions (HGs or thanatosomes) (arrowheads) are observed in the supranuclear cytoplasm. The size of the HGs reaches 14.5 mum. [bar = 2 mum (a), bar = 2 mum (b), bar = 5 mum (c)]. (D and E) Ultrastructural findings of the HGs in Case2. The neoplastic cells show prominent mucin production. Large-sized HGs (arrowheads) are observed in the supranuclear cytoplasm. The size of the reaches 21.6 mum. Exocrine (mucin) granules are seen just adjacent to the HGs. [bar = 5 mum (D), bar = 10 mum (E)].
IMCRJ-14-393-g0003.jpg
PMC8203267_02_IMCRJ-14-393-g0003.jpg
f0003
Case 1: Ultrastructurally, the HGs (or thanatosomes) were round in shape and homogenously electron-dense (Figure 3A-C). In addition to clustered electron-dense mucin granules, electron-dense, large globular inclusions (HGs) were observed in the supranuclear cytoplasm (Figure 3D and E).