{
  "abstract": "We report a case of intracholecystic papillary neoplasm (ICPN) with associated invasive carcinoma mimicking adenomyomatosis. A woman in her 60s presented with epigastric and back pain. Ultrasonography showed gallbladder wall thickening with expanded Rokitansky-Aschoff sinuses (RAS), and diffusion-weighted MRI revealed no restricted diffusion. Adenomyomatosis was suspected, and laparoscopic cholecystectomy was performed. Histopathology revealed ICPN with invasive carcinoma. Tumour extension into the RAS with replacement of the luminal epithelium suggested occlusion of the RAS opening and secondary expansion. Additional resection showed no residual disease. No recurrence was observed during 2-year follow-up. This case highlights a diagnostic pitfall in which ICPN may mimic adenomyomatosis and suggests that irregular RAS expansion should be interpreted with caution.",
  "authors": [
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Takahiko Omameuda"
    },
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Atsushi Miki"
    },
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Miku Mochizuki"
    },
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Makiko Tahara"
    },
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Hiroyuki Kitabayashi"
    },
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Mikio Shiozawa"
    },
    {
      "affiliations": [
        "Department of Pathology, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Shigeo Kawai"
    },
    {
      "affiliations": [
        "Department of Surgery, Tochigi Medical Center Shimotsuga, Tochigi, Japan"
      ],
      "name": "Masaru Koizumi"
    }
  ],
  "title": "Intracholecystic papillary neoplasm with associated invasive carcinoma mimicking adenomyomatosis",
  "uid": "c818eaae-157b-5550-b3dd-8f4a1b9e663e"
}