Clinical characteristics of papillary thyroid carcinoma arising from the pyramidal lobe

Abstract

Purpose Papillary thyroid carcinoma (PTC) arising from the pyramidal lobe is rare; therefore, clinicopathologic evaluation is lacking. In addition, the rate of occult malignancy in the pyramidal lobe after thyroid surgery is unclear. This study is to evaluate the clinical characteristics of PTCs that involve the pyramidal lobe. Methods The study enrolled 1,107 patients who underwent thyroid surgery for PTC at Seoul National University Hospital from 2006 to 2015. Pyramidal lobe status in pathologic reports was clear in all cases. “Pyramidal lobe-dominant PTC” was defined as single pyramidal lobe cancer or multifocal cancer with larger pyramidal lobe tumor. “Incidental pyramidal lobe PTC” was defined as occult cancer identified after thyroidectomy or as multifocal cancer with smaller pyramidal lobe tumor. Results Ten patients were included in the pyramidal lobe-dominant PTC group. The mean age was 58 ± 12.5 years, and the mean tumor size was 0.7 ± 0.7 cm. Cervical lymph node metastasis was found in 5 patients (50%). Three patients had microscopic lymphatic invasion, and 7 had advanced American Joint Comitee on Cancer (AJCC) stage disease (5 with stage III and 2 with stage IV). Compared with conventional PTC (n = 1,058), pyramidal lobe-dominant PTC was significantly associated with lymphatic invasion (P = 0.031) and advanced AJCC stage (P = 0.022). The prevalence of incidental pyramidal lobe PTC was 3.56%. Conclusion Pyramidal lobe PTC is relatively small in size; however, the rate of extrathyroidal extension and lymph node metastasis is high. Preoperative evaluation of nodal status is important, and the extent of surgery should be determined in accordance with the preoperative diagnosis.

Recurrence of papillary thyroid carcinoma from the residual pyramidal lobe: a case report and literature review

“…Sporadic cases of primary (instead of recurrent) PTC from the pyramidal lobe were reported. [13–16] Yoon et al enrolled 1107 patients with PTC in his study, finding the prevalence of occult malignancy in surgically resected pyramidal lobe tissue was 3.56%. [13] Ha et al reported a 48-year-old woman with primary PTMC in the PL and both thyroid lobes, and total thyroidectomy and central compartment neck dissection were performed for this patient.…”

“…[13–16] Yoon et al enrolled 1107 patients with PTC in his study, finding the prevalence of occult malignancy in surgically resected pyramidal lobe tissue was 3.56%. [13] Ha et al reported a 48-year-old woman with primary PTMC in the PL and both thyroid lobes, and total thyroidectomy and central compartment neck dissection were performed for this patient. [16] Santrac et al enrolled 753 patients with PTC from 2003 to 2013 in his institution, but only 3 patients (0.4%) suffered from solitary PTC primarily from the PL.…”

Ultrasound for the detection of the pyramidal lobe of the thyroid gland

“…Hence, it may be afflicted in generalized thyroid disease as well as multifocal thyroid carcinoma [6,7,10]. The PL has been reported as the primary site of papillary and folliculary thyroid carcinoma in multiple case series [11][12][13][14]. Although rare, papillary thyroid carcinoma arising from the PL was significantly associated with a more frequent lymphatic invasion, a higher tumor stage and a more advanced American Joint Committee on Cancer (AJCC) stage when compared to papillary carcinoma found elsewhere in the thyroid gland.…”

“…Although rare, papillary thyroid carcinoma arising from the PL was significantly associated with a more frequent lymphatic invasion, a higher tumor stage and a more advanced American Joint Committee on Cancer (AJCC) stage when compared to papillary carcinoma found elsewhere in the thyroid gland. Prevalence of papillary thyroid cancer stemming from or afflicting the PL was 4.4% (49/1107) [13]. Owing to its mostly delicate size, the PL may be overlooked during surgery and may be a potential site for recurrent disease [15][16][17].…”

Double Pyramidal Lobe of the Thyroid Gland

“…Remnant tissue after surgical operation may complicate the proper treatment of such diseases and the sensitive postoperative follow-up of patients. Based on its high incidence, the pyramidal lobe is considered as a normal component of the thyroid gland that may be affected by the diseases that affect the rest of the thyroid parenchyma and uncommonly harbor malignant disease ( 2 ). Anatomic variations of the gland, remnant pyramidal lobes, preclude complete removal of thyroid tissue, which can cause recurrent goiter.…”