Pseudolymphoma with atrophic parenchyma of the liver: Report of a case.

INTRODUCTION: Pseudolymphoma of the liver is a very rare disease. It is usually resected and pathologically diagnosed because of the difficulty of discrimination from the malignant neoplasm. For this reason, few cases which were observed for several years have been reported. We present a case of this disease observed and slightly enlarged for two years.

PRESENTATION OF CASES: The patient was a 46-year-old woman who underwent laparoscopic partial nephrectomy for right renal cell carcinoma two years ago. The preoperative computed tomography (CT) showed the mass 7 mm in diameter with localized parenchymal atrophy of the liver (segment Ⅵ). Two years later, CT showed enlarged mass from 7 to 11 mm in diameter. We performed laparoscopic partial hepatectomy because the patient desired definite diagnosis by surgery. The resected specimen showed white and solid mass. The lymphocyte and plasma cells are histologically observed. Immunohistological staining showed CD10 positive, Bcl-2 negative, and cyclin D1 negative. The pathological diagnosis was pseudolymphoma of the liver.

DISCUSSION: Pseudolymphoma is rarely observed in the liver. It is reported that chronic hepatitis, collagen diseases, and malignant diseases were often accompanied, but detail pathogenesis has been unknown. She had the history of renal carcinoma, but the lesion was not vanished regardless of clearance of renal neoplasm. Surgical resection is usually performed because discrimination with malignant neoplasm is difficult. The present case is probably the first one, which is followed for long term duration.

CONCLUSION: The present case may contribute to clarify the pathophysiology of this entity.