Cancer Res Treat.  2015 Jul;47(3):436-440. 10.4143/crt.2013.184.

Potential Role of Adjuvant Radiation Therapy in Cervical Thymic Neoplasm Involving Thyroid Gland or Neck

• Noh JM
• Ha SY
• Ahn YC
• Oh D
• Seol SW
• Oh YL
• Han J

• KMID: 2148492
• DOI: http://doi.org/10.4143/crt.2013.184

Abstract

PURPOSE
The purpose of this study is to assess the clinicopathologic features, treatment outcomes, and role of adjuvant radiation therapy (RT) in cervical thymic neoplasm involving the thyroid gland or neck.
MATERIALS AND METHODS
The medical and pathologic records of eight patients with cervical thymic neoplasm were reviewed retrospectively. All patients underwent surgical resection, including thyroidectomy or mass excision. Adjuvant RT was added in five patients with adverse clinicopathologic features. The radiation doses ranged from 54 Gy/27 fractions to 66 Gy/30 fractions delivered to the primary tumor bed and pathologically involved regional lymphatics using a 3-dimensional conformal technique.
RESULTS
Eight cases of cervical thymic neoplasm included three patients with carcinoma showing thymus-like differentiation (CASTLE) and five with ectopic cervical thymoma. The histologic subtypes of ectopic cervical thymoma patients were World Health Organization (WHO) type B3 thymoma in one, WHO type B1 thymoma in two, WHO type AB thymoma in one, and metaplastic thymoma in one, respectively. The median age was 57 years (range, 40 to 76 years). Five patients received adjuvant RT: three with CASTLE; one with WHO type B3; and one with WHO type AB with local invasiveness. After a median follow-up period of 49 months (range, 11 to 203 months), no recurrence had been observed, regardless of adjuvant RT.
CONCLUSION
Adjuvant RT after surgical resection might be worthwhile in patients with CASTLE and ectopic cervical thymoma with WHO type B2-C and/or extraparenchymal extension, as similarly indicated for primary thymic epithelial tumors. A longer follow-up period may be needed in order to validate this strategy.

Keyword

Thyroid neoplasms; Carcinoma; Thymus-like differentiation; Neck; Radiotherapy

MeSH Terms

Follow-Up Studies
Humans
Neck*
Radiotherapy
Recurrence
Retrospective Studies
Thymoma
Thymus Neoplasms*
Thyroid Gland*
Thyroid Neoplasms
Thyroidectomy
World Health Organization

Figure

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  Fig. 1. Representative dose distributions of three-dimensional conformal radiotherapy (A) and helical tomotherapy (B). The areas filled with red, brown, blue, yellow, pink, and light blue refer to 100%, 97%, 95%, 85%, 75%, and 50% of the prescribed dose, respectively. The clinical target volumes are delineated in sky blue.

• 

  Fig. 2. Representative photographs of cervical thymoma World Health Organization (WHO) type B1 (A), WHO type B3 (B), and carcinoma showing thymus-like differentiation (CASTLE) (C, D). (A) Cervical thymoma WHO type B1 is predominantly composed of immature lymphocytes, resembling the normal thymic cortex. (B) Cervical thymoma WHO type B3 is predominantly composed of medium-sized round or polygonal epithelial cells with mild atypia. (C) CASTLE is located in the thyroid gland and tumor cell nests are surrounded by fibrous stroma. Tumor cells show vesicular nuclei and prominent nucleoli (A-C, H&E staining, ×200). (D) CD5 is diffusely positive in tumor cells of CASTLE (×200).

Reference

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