Abstract
Objective: To report a case of thymic hyperplasia diagnosed three months after initiation of recombinant human growth hormone (GH) for the treatment of GH deficiency. Design: Retrospective chart review was conducted to evaluate the temporal relationship between treatment with GH and thymic enlargement in a 7-year-old girl who had a history of embryonal rhabdomyosarcoma of the nasopharynx diagnosed at the age of 3 years. Results: The diagnosis of GH deficiency was made based on clinical and auxological criteria, an insufficient response to clonidine-arginine stimulation testing (peak GH level of 4.8 μg/L) and low insulin-like growth factor 1 (IGF-1) level (30 ng/mL, -2.7 SD). The patient was started on GH at a dose of 0.3 mg/kg/week. At the initiation of treatment with GH, the baseline growth velocity was 0.8 cm/year (-6.0 SD) and height was 112.5 cm (-1.7 SD). After three months of treatment with GH, her height increased by 4.2 cm (from -1.7 to -1.2 SD), and the IGF-1 level from -2.7 SD to -1.1 SD. A chest CT performed at that time for recurrence surveillance showed 89% increase in thymic volume relative to previous scan before treatment with growth hormone. A thoracoscopic biopsy of the thymus was performed and revealed hyperplasia with normal thymic architecture without evidence of malignancy. Conclusions: The timing of the development of thymic hyperplasia, along with data from in vitro and in vivo animal studies showing that GH and IGF-1 can directly stimulate growth of the thymus, suggests that GH contributed to the development of thymic hyperplasia in this patient.
Original language | English (US) |
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Pages (from-to) | 41-46 |
Number of pages | 6 |
Journal | Growth Hormone and IGF Research |
Volume | 17 |
Issue number | 1 |
DOIs | |
State | Published - Feb 2007 |
Keywords
- Growth hormone deficiency
- Hematopoietic cell transplantation
- Immune system
- Insulin-like growth factor I
- Thymic rebound
- Thymus