Moriyama E, Yokose T, Kodama T, Matsuno Y, Hojo F, Takahashi K, Nagai K, Nishiwaki Y, Ochiai A
Pathology Division, National Cancer Center Research Institute East, Chiba, Japan.
Jpn J Clin Oncol. 2000 Aug;30(8):349-53. doi: 10.1093/jjco/hyd096.
Low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT-type lymphoma) is a rare thymic tumor, with only seven previous cases described worldwide to date. We describe the only case to have presented with pulmonary amyloid nodules. A 63-year-old Japanese female was found to have an anterior mediastinal tumor and multiple bilateral pulmonary nodules during a medical check-up in 1990 followed by chest radiography and computerized tomography. Because the mediastinal tumor grew larger, she was referred to the National Cancer Center Hospital East and hyperglobulinemia was pointed out. The thymus was resected through median sternotomy and pulmonary nodules were also resected through left thoracotomy. The solid and nodular tumor with several small satellite extensions and cyst formation was completely confined to within the thymus and the resected pulmonary nodules consisted of solid masses with a rough surface. Histologically, monotonous medium-sized centrocyte-like cells occupied the medulla of the thymus and infiltrated Hassall's corpuscles (lymphoepithelial lesions) and the resected pulmonary nodules consisted of eosinophilic amorphous deposits which showed birefringence on Congo Red staining. Immunohistochemically, the tumor cells were positive for CD20 and CD79a. IgG and kappa light chain restrictions were also found in plasmacytoid cells in the tumor. Clonal rearrangement of the immunoglobulin heavy chain gene was demonstrated by polymerase chain reaction. We diagnosed this case as low-grade B-cell MALT-type lymphoma in the thymus and nodular pulmonary amyloidosis. Since the patient had only localized amyloid deposits in the lung far from the thymic malignant lymphoma and had high serum immunoglobulins, the pulmonary amyloid deposits might be derived from a circulating precursor associated with hyperglobulinemia.
黏膜相关淋巴组织低度B细胞淋巴瘤（MALT型淋巴瘤）是一种罕见的胸腺肿瘤，迄今为止全球仅报道过7例。我们报告了唯一一例伴有肺淀粉样结节的病例。一名63岁的日本女性在1990年体检时经胸部X线和计算机断层扫描发现前纵隔肿瘤及双侧多发肺结节。由于纵隔肿瘤增大，她被转诊至国立癌症中心东医院，发现有高球蛋白血症。通过正中胸骨切开术切除胸腺，同时通过左胸切开术切除肺结节。实性和结节性肿瘤伴有多个小卫星灶及囊肿形成，完全局限于胸腺内，切除的肺结节为表面粗糙的实性肿块。组织学上，胸腺髓质内可见单一形态的中等大小中心细胞样细胞，浸润哈氏小体（淋巴上皮病变），切除的肺结节由嗜酸性无定形沉积物组成，刚果红染色呈双折射。免疫组化显示肿瘤细胞CD20和CD79a阳性。肿瘤中的浆细胞样细胞也发现有IgG和κ轻链限制。聚合酶链反应证实免疫球蛋白重链基因存在克隆重排。我们将该病例诊断为胸腺低度B细胞MALT型淋巴瘤及结节性肺淀粉样变性。由于患者仅在远离胸腺恶性淋巴瘤的肺部有局限性淀粉样沉积物，且血清免疫球蛋白升高，肺淀粉样沉积物可能来源于与高球蛋白血症相关的循环前体。
