Table 4.
Review of previously published reports and series of E-MTCs.
| Author, year [reference] | Description of reported E-MTCs (with definition of encapsulation when available) | E-MTC (%) | Capsule integrity (%) | Tumor size (mm) | Metastatic MTC (%), site | Biochemical Cure (%) |
|---|---|---|---|---|---|---|
| Williams et al., 1966 (24) | MTC sharply demarcated from the surrounding thyroid tissue by a complete or partial fibrous capsule | 9/67 (13.4) | 2/9 (22.2) | NR | NR | NR |
| Beskid, 1979 (25) | “C cell adenoma” surrounded by a thick hyaline capsule with no infiltration of the capsule by the nodule cells | 1/1 (100) | 1/1 (100) | 40 | 0 | 1/1 (100) |
| Kodama et al., 1988 (26) | “C cell adenomas” (one with incomplete very thin capsule without infiltrative growth) with positive Ctn and no CEA staining; low serum CEA | 1/2 (50) | 0/1 (0) | 40 (both) | 0 | 2/2 (100) |
| Driman et al., 1991 (27) | MTC surrounded by a distinct fibrous capsule with weak Ctn, CEA and CgA staining; normal-high serum Ctn and low serum CEA | 1/1 (100) | NR | 20 | 0 | 1/1 (100) |
| Ozkara et al., 2002 (28) | Encapsulated (intact capsule) papillary variant MTC with extensive cystic degeneration and positive Ctn, CEA, CgA staining | 1/1 (100) | 1/1 (100) | 40 | 0 | 1/1 (100) |
| Miccoli et al., 2007 (17) | MTCs divided in completely encapsulated and non-encapsulated | 18/70 (34.6) | 18/18 (100) | NR | 0 | 18/18 (100) |
| Santosh et al., 2011 (29) | Well-encapsulated HTA-like variant MTC with positive Ctn staining | 1/1 (100) | 1/1 (100) | 30 | 0 | 1/1 (100) |
| Bhat and Jena, 2012 (30) | Well-encapsulated HTA-like variant MTC with positive Ctn staining | 1/1 (100) | 1/1 (100) | 30 | 0 | NR |
| Aubert et al., 2018 (14) | MTCs with or without tumor capsule (not otherwise specified) | 21/54 (38.9) | NR | NR | 3 (14.3), N | 18/18 (100) |
| Cipri et al., 2019 (31) | Encapsulated microMTC with positive Ctn and CgA staining; undetectable serum Ctn | 1/1 (100) | NR | ≤ 10 | 0 | 1/1 (100) |
| Censi et al., 2019 (32) | Well-encapsulated “borderline tumor” (between adenoma and carcinoma) with weak CEA and no CgA staining; low serum CEA | 1/1 (100) | 1/1 (100) | 70 | 0 | 1/1 (100) |
| Alzumaili et al., 2020 (13) | MTCs divided in completely encapsulated/well circumscribed, partially encapsulated or totally lacking a capsule; capsular invasion defined as complete tumoral penetration of the capsule | 26/143 (18.2) | 8/26 (30.8) | NR | NR | NR* |
| Singh et al., 2020 (33) | Encapsulated papillary variant MTC with extensive cystic degeneration and positive Ctn and CgA staining | 1/1 (100) | NR | 80 | 1 (100), N | NR §§ |
| Moura et al., 2021 (15) | Collateral reporting of encapsulated MTC (not otherwise specified) | 8/65 (12.3) | NR | NR | 1 (12.5), N | NR |
| Machens et al., 2021 (18) | Tumor capsule integrity was classed into 5 subgroups: tumor capsule evenly demarcated; tumor capsule irregular but intact, with or without invasion; breach of the tumor capsule with ≤3 tumor extensions measuring ≤3 mm in width; breach of the tumor capsule with >3 tumor extensions or one tumor extension measuring >3 mm in width; diffuse tumor growth without tumor capsule. | 81/139 (58.3) | 47§/81 (58) | Between 7 and 12§§ (median) | 0 | 45/46§§§ (97.8) |
| Sum of published cases | 172/548 (31.4) | 80/140 (57.1) | – | 5 (2.9), N | 89/90 (98.9) | |
| Present series | 7/44 (15.9) | 4**/7 (57.1) | 0 | 7/7 (100) | ||
| Total cases | 179/592 (30.2) | 84/147 (57.1) | – | 5 (2.8), N | 96/97 (98.9) |
E-MTC, encapsulated medullary thyroid carcinoma; CEA, carcinoembrion antigen; CgA, cromogranin A; Ctn, calcitonin; HTA, hyalinizing trabecular adenoma; N, nodal metastases; NR, not reported.
*Tumor encapsulation improved loco-regional free survival but had no effect on disease specific survival and distant metastasis free survival.
§ Included cases with tumor capsule evenly demarcated, irregular but intact, or with less than 3 tumor extensions < 3 mm in width.
§§Only tumors with size ≤ 25 mm on histopathologic evaluation were included in the entire study.
**Only encapsulated tumors without full-thickness capsular invasion (albeit focal).
§§§One patient lost at follow-up.