PMC10206132_01
Abdominal injected CT-scan of a giant insulinoma in a 38-year-old female patient suffering from severe hypoglycemia. (A) Plain Computed Tomography scan (CT-scan); horizontal cut: the 88 mm-wide mass was observed in the left hypochondrium, without invasion of adjacent structures (dashed lines). (B) Plain Computed Tomography scan (CT-scan); tridimensional reconstruction: The absence of organ invasion was confirmed using three-dimensional reconstruction for computed tomography (arrow).
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An abdominal CT-scan was performed, which showed a heterogenous 88 x 73 mm bulky mass of the left hypochondrium located between the tail of the pancreas and the splenic hilum, without evidence of tissue infiltration or peripheral lymph node invasion ( Figure 1 ).
Gross description and histopathological analysis of a giant insulinoma in a 38-year-old female patient suffering from severe hypoglycemia. Positive detection of antibodies is indicated by brown staining. (A) (Photography - horizontal cut-section): Gross examination of the tumor following surgical resection and formalin fixation during 48 hours. The encapsulated tumor of approximately 80 mm of diameter shows well-defined borders and a homogenous whitish-grey appearance at cut-section with several hemorrhagic foci. (B) (HES, x 200): Histopathological analysis shows a monophasic proliferation of nests and cords of basophilic cells, organized around numerous vascular slits and inside a moderately thick fibrous capsule (arrow). No atypia, necrosis or capsular invasion were noted. The mitotic index was estimated at approximately 1 mitosis/10 hpf. (C) (HES, x 400): Endocrine cells were also surrounded by a hyaline stroma (arrow). (D) (Congo Red, x400) The hyaline stroma was negative for Congo Red staining (arrow). (E) (CD56, x 400): Tumor cells showed intense diffuse cytoplasmic staining. (F) (Synaptophysin, x 400): Tumor cells showed intense diffuse cytoplasmic staining. (G) (Chromogranin A, x 400): Tumor cells showed intense heterogeneous cytoplasmic staining. (H) (Neuron-Specific Enolase, x 400): Tumor cells showed weak diffuse cytoplasmic staining. (I) (Ki-67, x 400): The Ki-67 proliferation index was estimated around 1%. (J) (Insulin, x 400): Few scattered cells were positive for insulin immunostaining (arrow).
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At gross examination, the tumor was located at the pancreatic tail and measured approximately 90 x 85 x 50 mm, with at cut-section a whitish-grey homogenous appearance ( Figure 2A ). Histopathology showed proliferation of a homogenous population of small ovoid basophilic/amphophilic cells organized in nests, cords and trabeculae inside a thick fibrous capsule ( Figure 2B ), within a irregular hyalinized stroma ( Figure 2C ), negative at Congo Red staining ( Figure 2D ). Immunostaining revealed strong CD56 and synaptophysin positivity ( Figures 2E, F , respectively), heterogenous chromogranin positivity ( Figure 2G ) and weak diffuse positivity of neuron-specific enolase (NSE) ( Figure 2H ). The proliferative index Ki-67 remained lower than 2% ( Figure 2I ). Weak and focal cytoplasmic staining of insulin was noted in tumor cells ( Figure 2J ).