Ectopic bone formation and extramedullary hematopoiesis in the thyroid gland: report of a case and literature review

Heterotopic bone formation with extramedullary haematopoiesis in a thyroid nodule

The presence of mature bone and bone marrow in the thyroid gland is an exceedingly rare occurrence. Extramedullary haematopoiesis (EMH) and heterotopic bone formation (HBF) should be suspected when cytology of thyroid nodules reveals evidence of megakaryocytes or bone marrow fat, respectively. The cause of these abnormalities has not been fully elucidated, but the role of bone morphogenic factors (BMPs) in their pathogenesis has been suggested. Both EMH and HBF can be seen in both benign and malignant primary thyroid conditions, and although they have not been definitively associated with significant pathology, it is recommended that extension studies be considered in the event of these findings to rule out concomitant haematological conditions.

Osseous Metaplasia and Ectopic Bone Formation in a Patient With Hashimoto's Thyroiditis

Thyroid nodules are frequently accompanied by degenerative changes, such as hemorrhage, cholesterol crystallization, fibrous tissue deposition, or filling with fat. Although calcification is also a common phenomenon, osteogenesis, characterized by mature bone formation, is very rare. Here, we describe a case of Hashimoto's thyroiditis with osseous metaplasia and ectopic bone formation case and discuss its possible causes.

Adrenal extramedullary haematopoiesis: an unusual incidentaloma

We report a case of adrenal extramedullary haematopoiesis in a 24-year-old women who presented with pallor and weakness. Ultrasonography of the abdomen detected moderate hepatosplenomegaly with multiple lesions in the spleen and an incidental right adrenal mass. There was no ascites or lymphadenopathy. CT scan revealed a heterogeneous right adrenal mass with multiple non-enhancing lesions in the spleen. Ultrasound guided trucut biopsy was performed after excluding a functioning tumour, which confirmed the diagnosis. Later, she was diagnosed to have haemoglobin E/beta thalassaemia and was put on hydroxyurea trial.

A rare presentation: A case report of osseous metaplasia and mature bone formation in a follicular adenoma of the thyroid

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Osseous metaplasia and bone formation may be seen in a broad spectrum of diseases involving the thyroid gland especially in malignant neoplasms of the thyroid gland.

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However, this differentiation is not unique to malignant neoplasms. It may also be encountered in follicular adenomas of the thyroid.

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Awareness of thyroid nodules undergoing hemorrhagic, cystic, and fibrotic changes, as well as calcification and ossification is paramount in proper diagnosis and treatment of these pathologies.

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Particularly, patient’s history, associated risk factors and clinical presentation are the most important factors to consider in clinical differentiation of malignant and benign diagnoses.

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All ossifications in a thyroid nodule should be considered suspicious for malignancy until proven otherwise.

Introduction

Cases of multinodular goiter, thyroid hyperplasia, follicular adenoma, papillary thyroid carcinoma, and anaplastic thyroid carcinoma have been reported with histopathologic findings of osseous metaplasia (OM), bone marrow metaplasia (BMM), ectopic bone formation (EBF), ossification, and extramedullary hematopoiesis (EMH). To date no report of a follicular adenoma with OM and mature EBF in the absence of EMH has been reported in the English language.

Presentation of case

63-year-old woman with an incidental finding of thyroid nodule unable to be biopsied. One area was found to contain OM with mature EBF and without vascular invasion. The surrounding tissue was unremarkable, and no malignancy was found.

Discussion

Ectopic bone formation and osseous metaplasia in a thyroid nodule has an extensive differential diagnosis, from thyroid related pathologies to parathyroid causes, congenital syndromes, and hamartomas. A common theory amongst these is the role of basic fibroblast growth factor (bFGF) and bone morphogenetic protein-2 (BMP-2), signaling factors involved in cellular proliferation and growth.

Conclusion

This is the first case report of a follicular adenoma with OM and EBF in the absence of EMH. In this case, this adenoma was an incidental finding and the patient had no symptoms or accompanying laboratory abnormalities. Her benign presentation underscores the importance of awareness of the more common changes a thyroid nodule can undergo, such as hemorrhagic, cystic, and fibrotic changes, as well as the rarer changes of calcification with eventual ossification.

Extracellular Superoxide Dismutase Expression in Papillary Thyroid Cancer Mesenchymal Stem/Stromal Cells Modulates Cancer Cell Growth and Migration

Tumor stroma-secreted growth factors, cytokines, and reactive oxygen species (ROS) influence tumor development from early stages to the metastasis phase. Previous studies have demonstrated downregulation of ROS-producing extracellular superoxide dismutase (SOD3) in thyroid cancer cell lines although according to recent data, the expression of SOD3 at physiological levels stimulates normal and cancer cell proliferation. Therefore, to analyze the expression of SOD3 in tumor stroma, we characterized stromal cells from the thyroid. We report mutually exclusive desmoplasia and inflammation in papillary and follicular thyroid cancers and the presence of multipotent mesenchymal stem/stromal cells (MSCs) in non-carcinogenic thyroids and papillary thyroid cancer (PTC). The phenotypic and differentiation characteristics of Thyroid MSCs and PTC MSCs were comparable with bone marrow MSCs. A molecular level analysis showed increased FIBROBLAST ACTIVATING PROTEIN, COLLAGEN 1 TYPE A1, TENASCIN, and SOD3 expression in PTC MSCs compared to Thyroid MSCs, suggesting the presence of MSCs with a fibrotic fingerprint in papillary thyroid cancer tumors and the autocrine-paracrine conversion of SOD3 expression, which was enhanced by cancer cells. Stromal SOD3 had a stimulatory effect on cancer cell growth and an inhibitory effect on cancer cell migration, thus indicating that SOD3 might be a novel player in thyroid tumor stroma.

Thyroid Sporadic Goiter with Adult Heterotopic Bone Formation

Thyroid heterotopic bone formation (HBF) in goiter is a rare finding. Five thyroid resection specimens were analyzed for HBF. The results were correlated with clinicomorphological features. All patients were women (33–82 years). The preoperative diagnosis was thyroid goiter or nodule. Treatment consisted in thyroidectomy and lobectomy (3 and 2, resp.). Microscopy showed sporadic nodular goiter. Malformative blood vessels and vascular calcifications were seen in intra- and extrathyroid location (5 and 3, resp.). The number and size of HBFs (total: 28) ranged between 1 and 23/thyroid gland (one bilateral) and 1 and 10 mm, respectively. Twelve HBFs were in contact with the thyroid capsule. Most were extranodular (21, versus 6 intranodular). The medical history was positive for dyslipidemia, hyperglycemia, renal dysfunction, and hyperuricemia (2, 3, and 3 cases and 1 case, resp.) without any parathyroid abnormality. In conclusion, thyroid HBF may be characterized by subcapsular or extranodular location, various size (usually ≥2 mm), and vascular calcifications and malformations. Features of metabolic syndrome and renal dysfunction may be present, but their exact role in the pathogenesis of HBFs remains to be elucidated.

Extramedullary hematopoiesis: Elucidating the function of the hematopoietic stem cell niche (Review)

Extramedullary hematopoiesis (EMH) occurs under various circumstances, including during embryonic/developmental periods, pathological status secondary to insufficient bone marrow function or ineffective hematopoiesis, in hematological disorders, for example malignancies, as well as stromal disorders of the bone. EMH is characterized by hematopoietic cell accumulations in multiple body locations. Common EMH locations observed in clinical and pathological practice include the spleen, liver, lymph nodes and para‑vertebral regions. Among the various organs associated with EMH, the spleen offers a unique site for evaluation of hematopoietic stem cell (HSC)/niche interactions, as this organ is one of the most common sites of EMH. However, the spleen does not have a major role in embryonic/developmental hematopoiesis. A recent study by our group revealed that circulating HSCs may be trapped by chemokine (C‑X‑C motif) ligand 12 (CXCL12)‑positive cells at the margin of sinuses near CXCL12‑positive endothelial cells, resulting in the initiation of the first step of EMH, which is a similar mechanism to bone marrow hematopoiesis. The present review briefly discusses the environment of EMH in extramedullary spaces in order to investigate the mechanisms underlying HSC maintenance, and aid the elucidation of the niche‑stem cell interactions that occur in the bone marrow.

Extramedullary hematopoiesis within cystic renal cell carcinoma with oncocytic and chromophobe cell types: A case report

Extramedullary hematopoiesis (EMH) is a phenomenon in which hematopoietic cells are found in sites other than the bone marrow. It is usually observed in the liver and spleen but may occasionally be found within solid tumors. The current case report presents a 69-year-old female patient who presented with a renal cyst. Histopathological examination following surgical removal of the cyst revealed a lining of oncocytic- and chromophobe-type cells with capsular invasion and a mass forming EMH with evident bone trabeculae within the cyst wall. Circulating hematopoietic stem cells in the blood and their colonization within tissues is discussed in the present case report, emphasizing certain types of renal cell carcinoma.

Osseous metaplasia with mature bone formation of the thyroid gland: Three case reports

Nodular hyperplasia (nodular or multinodular goiter) is the most common form of thyroid disease. These nodules may undergo secondary changes in the form of hemorrhages, calcification and cystic degeneration. However, osseous metaplasia with mature bone formation rarely occurs. The present study reports the cases of three female patients with thyroid nodules diagnosed as nodular hyperplasia with osseous metaplasia and mature bone formation. The patients underwent right lobectomy, near total thyroidectomy and total thyroidectomy, respectively. The clinical course of the patients following resection were unremarkable.

Hydatid cyst of the thyroid gland: report of three cases

Cystic Echinococcosis is a parasitic infestation that is distributed world-wide. It may be found in nearly any part of the body, most often in the liver and the lungs, but occasionally in other structures such as the thyroid gland. The present study reports three cases of hydatid cysts of the thyroid gland, in patient ranging from 18 to 25 years of age. Two patients had concomitant hydatid disease involving organs other than the thyroid gland (secondary disease), and one had, sole, involvement of the thyroid gland itself (primary disease). Moreover, an occult papillary thyroid carcinoma was detected incidentally in one case, involving the unilateral thyroid lobe as the hydatid cyst. While several surgical procedures including left lobectomy and isthmectomy were undertaken in one patient, two patients underwent total thyroidectomy. No disease recurrence was observed in any of the three patients during the postoperative follow-up period. No study reporting the concomitance of hydatid cyst and neoplasia of the thyroid gland has been previously published. This concomitance indicates the importance of the differential diagnosis of lesions characterized by calcifications in the thyroid gland, especially in endemic regions.