Micronodular thymic tumor with lymphoid stroma: A case report and review of the literature

Table 2 Summary of cases in the literature

Variable item	Number of cases	Percentage (%)
Age (median, age span)	63, 41-83	-
Sex
Male	51	53.7
Female	44	46.3
Benignity and malignancy[2,27]
Benign (MNT)	77	81.1
Malignancy (MNC)	18	18.9
Site
Thymic source	92	96.8
Extra-thymic source	3	3.2
Clinical symptoms
No obvious symptoms	76	80.0
Local symptoms	11	11.6
Immune related symptoms	8	8.4
Masaoka stage
1	52	59.8
2a	16	18.4
2b	13	14.9
3	4	4.6
4	2	2.3
Tumor size (cm) (mean, standard deviation, size span)	5.14 ± 2.32, 1.2-10	-
Tumor cross section
Cystic or cystic and solid	35	44.3
Solid	44	55.7
Tumor cell atypia
No	58	66.7
Mild	6	6.9
Moderate	7	8.0
Severe	16	18.4
Mitotic figures[25]
≤ 2/10 HPF	62	78.5
2/10 HPF	17	21.5
Necrosis
No	38	77.6
Yes	11	22.4
CD5 staining in tumor cells
Negative	43	79.6
Focally positive or diffusely positive	11	20.4
Ki-67 staining[25]
≤ 2% of tumor cells	15	51.7
2% to 10% of tumor cells	5	17.2
≥ 10% of tumor cells	9	31.0
TdT positive lymphocytes
No	12	42.9
Few	7	25.0
Many	9	32.1
Treatment
Resection	84	93.3
Resection + radiotherapy or chemotherapy	4	4.4
Radiotherapy + chemotherapy	1	1.1
No treatment	1	1.1
Follow-up time	2 d to 22 yr
Follow-up results
Loss to follow-up	18	21.2
No relapse or metastasis	60	70.6
Tumor relapse	1	1.2
Death caused by nontumorous reason	5	5.8
Tumor-caused death	1	1.2

HPF: High power fields.