Temporal Evolution of Histologic and Cell-Kinetic Parameters of Recurrent and Metastatic Thymic Neoplasms.
Anja C Roden, Eunhee S Yi, Janis L Donovan, Stephen D Cassivi, Yolanda I Garces, Randolph S Marks, Marie Christine Aubry. Mayo Clinic, Rochester
Background: Thymic neoplasms are generally considered as low grade malignancies, which can recur or metastasize. The temporal evolution of histologic and cell-kinetic features in recurring and metastasizing thymic neoplasms has not been studied.
Design: Medical records from 15 patients (pts) (0.05%) treated for thymic neoplasm, 1970-2006, who developed recurrence (recur) and/or metastasis (met) were reviewed. Two pathologists classified all cases (WHO) with consensus diagnosis. Ki-67 LI was expressed as %pos/100 epithelial cell (EC) nuclei (mean of 1000 EC counted over 3 areas) and mitotic activity (MA) as mitoses/10Hpf (mean of 50Hpf counted).
Results: 10 men & 5 women with a median age of 50.3 yrs underwent complete resection of the original tumor (OT) (n=14), or had a biopsy (n=1). 7 pts had additional therapy. Masaoka stages were I (n=2), II (n=6), III (n=5), IV (n=2). OTs were classified as WHO types A (n=1, 6.7%), B1 (n=2, 13.3%), B2 (n=7, 46.7%), B3 (n=2, 13.3%), thymic carcinoma (n=2, 13.3%), atypical thymic carcinoid (n=1, 6.7%). For comparison, all thymic neoplasms treated during that time were classified as A (10.9%), AB (16.1%), B1 (22.3%), B2 (27.4%), B3 (12.4%), thymic carcinoma (7.3%), others (3.6%). Pts had 1 (n=5), 2 (n=4), or 3 (n=2) recurrences. 13 pts had mets, 8 of which also had recurrence(s). The mean interval between initial therapy and 1st recur/met was 6.0 yrs (range, 0 – 14.2 yrs). 30 resection specimens and 7 biopsies were evaluated for histology, Ki67 LI (n=33), and MA (n=31). In 5 cases, WHO type of the recur/met was different from the OT (Table 1).
|Original tumor (OT)||1st recur/met||2nd recur/met||3rd recur/met|
|Case||WHO (yrs after OT)|
|2||B2||B2 (2.5)||B3 (5.7)||Thymic carcinoma (13.4)|
|9||B2||B2 (4.4)||B3 (10.2)|