Ann Hepatobiliary Pancreat Surg.  2021 May;25(2):287-292. 10.14701/ahbps.2021.25.2.287.

Inflammatory myofibroblastic tumors arising from pancreas head and peri-splenic area mimicking a malignancy

• Jang EJ
• Kim KW
• Kang SH
• Pak MG
• Han SH

• KMID: 2516331
• DOI: http://doi.org/10.14701/ahbps.2021.25.2.287

Abstract

Inflammatory myofibroblastic tumors (IMTs) are a rare chronic inflammatory disease with unclear pathogenesis and pathological features that are not those of a malignant tumor. It is difficult to differentially diagnose them without surgical excision because of their unpredictable clinical behavior, which ranges from benign to locally invasive aggressiveness. We report two cases of IMTs that were diagnosed after surgery. In one case, the IMT originated in peri-splenic area in a 63-year-old female patient. The other case involved a 48-year-old female patient who suffered from an IMT of the head of the pancreas. Both of these cases did not require further treatment based on histological findings, and there has been no evidence of recurrence or metastasis so far. These cases show that the primary choice for the exact diagnosis and proper treatment of IMTs is complete surgical resection.

Keyword

Inflammatory myofibroblastic tumor; Pancreas; Retroperitoneum; Case report

Figure

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  Fig. 1 (A, B) Abdominal CT shows 10 cm heterogenous mass.

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  Fig. 2 The histopathological evaluation shows a well-circumscribed whitish mass characterized by the proliferation of spindle cells mixed with inflammatory cells such as lymphocytes and plasma cells, compatible with Inflammatory myofibroblastic tumor. ×10 magnification (A), ×100 magnification (B), ×400 magnification (C).

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  Fig. 3 Two years after surgery, CT shows no local recurrence and metastasis.

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  Fig. 4 Initial abdominal CT (A, B), MRI (C) and PET (D) images show 7.5 cm mass in the head of pancreas.

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  Fig. 5 (A) The tumor is composed of fascicles of plump spindle cells with oval nuclei and small nucleoli (arrows). Inflammatory cells, mostly plasma cells are seen either as small aggregates or more uniformly dispersed (dot-lined circle) (H-E stain, ×400 magnification). (B) The tumor cells show focal immunohistochemical positivity for smooth muscle actin (SMA, ×400 magnification). (C) Immunohistochemical staining for IgG4, a marker of IgG4-positive plasma cell shows only one positive IgG4-positive cell per high power field (dot-lined circle) (IgG4, ×400 magnification). (D) Ki-67 proliferation index is about 5% (Ki-67, ×400 magnification).

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  Fig. 6 After 6 month, no evidence of recurrence is observed in the CT.

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