Review of Heterotopic Thyroid Autotransplantation

Abstract

Total thyroidectomy is increasingly accepted for the management of bilateral benign thyroid disorders. Postoperatively, patients require lifelong levothyroxine replacement therapy to avoid postoperative hypothyroidism, which besides the burden of compliance, has been proven to be associated with several long-term side effects. Heterotopic thyroid autotransplantation was proposed several decades ago to avoid the need for life-long postoperative replacement therapy with maintaining the autoregulatory mechanism of thyroxin production inside the body according to its needs. Available data regarding this topic in literature is relatively poor. Before applying thyroid autotransplantation on humans, several studies have been done on animals, where the autologous transplantations were found to be successful in almost all the cases, proved by follow up postoperative 8-week measurements of thyroid hormones and histopathological examination of the removed autografts. Regarding the clinical application, few trials have been done using cryopreserved in vivo, in vitro or immediately autotransplanted thyroid autografts. Satisfactory results were obtained, however, the number of these studies and the number of patients per each study was very low. Besides the study methodologies were not so consistent.

Thyroidosis Mistaken for Thyroid Cancer

“…Thyroidosis refers to the development of parasitic thyroid implants, typically arising following thyroid surgery or trauma to the neck . The viability of heterotopic thyroid tissue following autotransplantation provides mechanistic proof-of-concept . Medical records for this patient documenting lymph node metastases reveal the difficulty in distinguishing lymph node involvement from aberrant thyroid tissue.…”

Subcutaneous transplantation of human thyroid tissue into a pre-vascularized Cell Pouch™ device in a Mus musculus model: Evidence of viability and function for thyroid transplantation

“…The TT literature is quite heterogeneous and generally considered controversial because it is primarily composed of historical reports, experimental animal studies and small case series [ 3 ]. This literature is extremely inconsistent in terms of the preoperative transplant thyroid pathology, whether fresh or cryopreserved tissue is transplanted, the transplant volume, the anatomical site for transplantation, the protocols for transplant functional evaluation and monitoring, and virtually all other procedural details [ 3 ]. Our approach to TT, in which thyroid tissue is transplanted into an implanted prevascularized medical device, is unique and may have clinical benefit over other methods.…”

“…Interestingly, the study of thyroid transplantation (TT) as a treatment for hypothyroidism after thyroidectomy, was actually reported greater than a century ago, prior to the isolation of thyroxine [ 2 ]. Despite small preclinical and clinical studies having demonstrated its feasibility and promise, and parathyroid autotransplantation, an analogous endocrine surgical procedure, being commonly performed and well accepted world-wide, TT has only undergone very limited investigation [ 3 , 4 ]. This is mainly because of tolerance of life-long dependence on LT4, along with an acceptance of the associated loss of the endogenous autoregulatory mechanisms of thyroid hormone production largely due to lack of any therapeutic alternatives, that have become etched into current medical thinking and clinical dogma.…”

Cryopreserved Rat Thyroid Autotransplantation in the Treatment of Postoperative Hypothyroidism

“…The efficacy of a permanent hormone replacement in the presence of postoperative hypothyroidism may be limited by the patient's lack of adherence to treatment, inadequate dose administration, malabsorption, among other reasons. In addition, free T4 treatment for a prolonged period may trigger deleterious side effects in patients with cardiovascular diseases, diabetes, using anticoagulant drugs, and women in the postmenopausal period (1,8,9). A multicenter study found that approximately 50% of patients undergoing such treatment had thyroid stimulating hormone (TSH) levels within the normal range (10).…”