Castleman disease is a polyclonal lymphoproliferative disease which is clinically classified into unicentric (UCD) and multicentric (MCD). TAFRO syndrome is a relatively new concept that partly overlaps with MCD. Due to their rarity, their incidence remains unknown. This study investigated the incidence and prevalence of UCD, MCD, and TAFRO syndrome in Japan using a fixed-point observation method based on their incidence in Ishikawa prefecture. The annual incidences of MCD, UCD, and TAFRO syndrome in Japan were 309-731, 71-542, and 110-502, respectively, yielding annual incidence rates per million individuals of 2.4-5.8, 0.6-4.3, and 0.9-4.9, respectively, and nationwide prevalence of 4,180-14,900, 1,350-10,300, and 860-7,240, respectively. In conclusion, MCD, UCD and TAFRO syndrome may not be as rare as previously estimated in Japan.
Primary intraocular lymphomas frequently develop into central nervous system lymphomas and vice versa. This study reviewed 22 consecutive patients with primary intraocular lymphoma diagnosed by immunostaining of vitrectomy cell blocks, and examined whether they developed central nervous system lymphoma. Seventeen patients developed central nervous system lymphoma: 3 patients developed intraocular and central nervous system lymphoma simultaneously, 9 patients developed central nervous system lymphoma 1 month to 5 years (median, 3 months) after intraocular lymphoma, and 5 patients developed central nervous system lymphoma preceding the diagnosis of intraocular lymphoma by 3 months to 9 years and 8 months (median, 1.5 years). In contrast, 5 patients did not develop central nervous system lymphoma: 2 patients did not develop local recurrence or central nervous system lymphoma in the follow-up period of 5 years and 11 years, respectively, after vitrectomy alone without additional local or systemic treatment. The remaining 3 patients with intraocular lymphoma had insufficient follow-up periods to determine the prognosis. The results of CD5 immunostaining of vitrectomy specimens were found in pathology reports of 8 patients: 3 patients with CD5-positive large cells and 4 patients with CD5-negative large cells developed central nervous system lymphoma. In summary, only a small number of patients did not develop central nervous system lymphoma based on long-term follow-up after vitrectomy alone. CD5 was not a marker of central nervous system involvement in this study population.