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Ectopic TSH-secreting pituitary tumor: a case report and review of prior cases.

Song M, Wang H, Song L, Tian H, Ge Q, Li J, Zhu Y, Li J, Zhao R, Ji HL - BMC Cancer (2014)

Bottom Line: TRH stimulating test was negative, whereas octreotide inhibition test showed a reduction in TSH by 30.8%.Furthermore, a large space-occupying lesion located at the nasopharynx was found by computed tomography and magnetic resonance imaging (MRI).The characteristics and successful interventions summarized in this report provide a guideline for clinicians.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology, Weihai Municipal Hospital, 70 Heping Road, Weihai, Shandong 264200, China. whsmq1201@hotmail.com.

ABSTRACT

Background: Ectopic TSH-secreting pituitary adenoma (TSH-oma) is a very unusual disorder. To date, there are only four cases reported. It is difficult to distinguish ectopic cases from both regular TSH-omas and resistance to thyroid hormone (RTH).

Case presentation: A newly identified case of ectopic TSH-oma arising from the nasal pharynx was described, and reports of four prior cases were reviewed. The patient was a 41-year-old male who developed what appeared to be typical hyperthyroidism and atrial fibrillation in 2009. Thyroid function tests showed elevated basal levels of free T3 (FT3, 24.08 pmol/L), free T4 (FT4, 75.73 pmol/L), and serum TSH (7.26 μIU/ml). Both TSH-oma and resistance to thyroid hormone syndrome were considered. TRH stimulating test was negative, whereas octreotide inhibition test showed a reduction in TSH by 30.8%. Furthermore, a large space-occupying lesion located at the nasopharynx was found by computed tomography and magnetic resonance imaging (MRI). A normal pituitary was visualized. Ectopic TSH-oma was preliminarily established. Using an endoscopic endonasal approach, the tumor was resected. Histological features and immunophenotypes were consistent with those of TSH-secreting tumor. The levels of both free thyroxine and TSH returned to normal ranges the day after surgery and remained within normal range for 48 months.

Conclusions: Although exceedingly rare, ectopic TSH-oma should be considered for patients with inappropriate secretion of TSH with hyperthyroidism and pituitary tumor undetectable by computed tomography and MRI. To our knowledge, this is the first case followed up more than 4 years. The characteristics and successful interventions summarized in this report provide a guideline for clinicians.

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Histological examination of resected tumor tissue. A &B, Histological examination of resected tumor tissue (×200). A, Irregular cells showing tumor tissue invasive growth involving the submucosa. B, Cytoplasm is filled with fine granules in tumor cells. C &D, Immunohistochemical detection of TSH and GH (×200). C, Most tumor cells express TSH (brown). D, Expression of GH in tumorous cells. E &F, Electron microscopy examination of tumor tissue. Numerous round electron dense granules about 100-200 nm in size are seen in the cytosol. Bar = 0.5 μm.
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Fig3: Histological examination of resected tumor tissue. A &B, Histological examination of resected tumor tissue (×200). A, Irregular cells showing tumor tissue invasive growth involving the submucosa. B, Cytoplasm is filled with fine granules in tumor cells. C &D, Immunohistochemical detection of TSH and GH (×200). C, Most tumor cells express TSH (brown). D, Expression of GH in tumorous cells. E &F, Electron microscopy examination of tumor tissue. Numerous round electron dense granules about 100-200 nm in size are seen in the cytosol. Bar = 0.5 μm.

Mentions: The patient underwent endoscopic endonasal surgery, through which the mass was removed in November 2009. Pathological examination confirmed invasive ectopic pituitary tumor extending to the bone parenchyma. Microscopic examination showed that the unenveloped tumor tissue lay beneath the nasal mucosa (pseudostratified ciliated columnar epithelium) (Figure 3A & B). The tumor cells invading the mucosa and fibrous tissue led to a tumor tissue type that was diffusive, solid lesion, and sinusoidal. The irregular tumor cells were mostly round or polygonal, while others were spindle shaped, filled with rich cytoplasm bearing fine particles. Some cells were found to have a round to ovoid nucleus with transparent cytoplasm (Figure 3A & B). Immunohistochemical assays detected expression of TSH (brown) and GH (brown) (Figure 3C & D). No other pituitary hormones, including ACTH, LH, FSH, and PRL, or thyroglobulin and thyroid transcription factor1 were detectable. In contrast, pan-cytokeratin, chromogranin, synaptophysin, and neuron specific enolase were detected. Electron microscopy examination found that the tumor was composed of pleomorphic cells (Figure 3E and F). Round, unenveloped electron-dense granules were dispersed throughout the cytoplasm. Some granules formed clusters. The diameter of granules was 0.1-0.2 μm.Figure 1


Ectopic TSH-secreting pituitary tumor: a case report and review of prior cases.

Song M, Wang H, Song L, Tian H, Ge Q, Li J, Zhu Y, Li J, Zhao R, Ji HL - BMC Cancer (2014)

Histological examination of resected tumor tissue. A &B, Histological examination of resected tumor tissue (×200). A, Irregular cells showing tumor tissue invasive growth involving the submucosa. B, Cytoplasm is filled with fine granules in tumor cells. C &D, Immunohistochemical detection of TSH and GH (×200). C, Most tumor cells express TSH (brown). D, Expression of GH in tumorous cells. E &F, Electron microscopy examination of tumor tissue. Numerous round electron dense granules about 100-200 nm in size are seen in the cytosol. Bar = 0.5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4125694&req=5

Fig3: Histological examination of resected tumor tissue. A &B, Histological examination of resected tumor tissue (×200). A, Irregular cells showing tumor tissue invasive growth involving the submucosa. B, Cytoplasm is filled with fine granules in tumor cells. C &D, Immunohistochemical detection of TSH and GH (×200). C, Most tumor cells express TSH (brown). D, Expression of GH in tumorous cells. E &F, Electron microscopy examination of tumor tissue. Numerous round electron dense granules about 100-200 nm in size are seen in the cytosol. Bar = 0.5 μm.
Mentions: The patient underwent endoscopic endonasal surgery, through which the mass was removed in November 2009. Pathological examination confirmed invasive ectopic pituitary tumor extending to the bone parenchyma. Microscopic examination showed that the unenveloped tumor tissue lay beneath the nasal mucosa (pseudostratified ciliated columnar epithelium) (Figure 3A & B). The tumor cells invading the mucosa and fibrous tissue led to a tumor tissue type that was diffusive, solid lesion, and sinusoidal. The irregular tumor cells were mostly round or polygonal, while others were spindle shaped, filled with rich cytoplasm bearing fine particles. Some cells were found to have a round to ovoid nucleus with transparent cytoplasm (Figure 3A & B). Immunohistochemical assays detected expression of TSH (brown) and GH (brown) (Figure 3C & D). No other pituitary hormones, including ACTH, LH, FSH, and PRL, or thyroglobulin and thyroid transcription factor1 were detectable. In contrast, pan-cytokeratin, chromogranin, synaptophysin, and neuron specific enolase were detected. Electron microscopy examination found that the tumor was composed of pleomorphic cells (Figure 3E and F). Round, unenveloped electron-dense granules were dispersed throughout the cytoplasm. Some granules formed clusters. The diameter of granules was 0.1-0.2 μm.Figure 1

Bottom Line: TRH stimulating test was negative, whereas octreotide inhibition test showed a reduction in TSH by 30.8%.Furthermore, a large space-occupying lesion located at the nasopharynx was found by computed tomography and magnetic resonance imaging (MRI).The characteristics and successful interventions summarized in this report provide a guideline for clinicians.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology, Weihai Municipal Hospital, 70 Heping Road, Weihai, Shandong 264200, China. whsmq1201@hotmail.com.

ABSTRACT

Background: Ectopic TSH-secreting pituitary adenoma (TSH-oma) is a very unusual disorder. To date, there are only four cases reported. It is difficult to distinguish ectopic cases from both regular TSH-omas and resistance to thyroid hormone (RTH).

Case presentation: A newly identified case of ectopic TSH-oma arising from the nasal pharynx was described, and reports of four prior cases were reviewed. The patient was a 41-year-old male who developed what appeared to be typical hyperthyroidism and atrial fibrillation in 2009. Thyroid function tests showed elevated basal levels of free T3 (FT3, 24.08 pmol/L), free T4 (FT4, 75.73 pmol/L), and serum TSH (7.26 μIU/ml). Both TSH-oma and resistance to thyroid hormone syndrome were considered. TRH stimulating test was negative, whereas octreotide inhibition test showed a reduction in TSH by 30.8%. Furthermore, a large space-occupying lesion located at the nasopharynx was found by computed tomography and magnetic resonance imaging (MRI). A normal pituitary was visualized. Ectopic TSH-oma was preliminarily established. Using an endoscopic endonasal approach, the tumor was resected. Histological features and immunophenotypes were consistent with those of TSH-secreting tumor. The levels of both free thyroxine and TSH returned to normal ranges the day after surgery and remained within normal range for 48 months.

Conclusions: Although exceedingly rare, ectopic TSH-oma should be considered for patients with inappropriate secretion of TSH with hyperthyroidism and pituitary tumor undetectable by computed tomography and MRI. To our knowledge, this is the first case followed up more than 4 years. The characteristics and successful interventions summarized in this report provide a guideline for clinicians.

Show MeSH
Related in: MedlinePlus