cribriform-morular variant of papillary thyroid carcinoma

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gist. Her family history was notable for memberswith both hyperthyroidism and hypothyroidism; amaternal grandmother had colonic polyps at theage of 70.On physical examination, she had a 2 3 2 cm,firm, mobile nodule of the left thyroid lobe. No palpablecervical or supraclavicular lymphadenopathywas found. Ultrasound demonstrated a 2.1-cmmass in the left thyroid lobe as well as a 5-mmnodule in the isthmus. A thyroid scan revealed acold left thyroid nodule. A fine-needle aspiration(FNA) biopsy specimen demonstrated cells suspiciousfor follicular neoplasia. Thyroid functiontests were normal. On review of her disease by ourinstitution, concern was raised for a PTC. Thepatient underwent a total thyroidectomy. Postoperatively,colonoscopy revealed a normal colonwithout polyposis.The final pathology report revealed a 2.05-cmPTC of the left thyroid lobe. The tumor was well differentiatedand did not have capsular or vascularinvasion, extrathyroidal extension, or multicentricity.Of note, the tumor was a ‘cribriform-morularvariant’ of PTC and demonstrated intermingled cribriform,follicular, papillary, trabecular, and morulararchitecture (Figure 1). The remainder of thethyroid had nodular hyperplasia. Immunohistochemically,the tumor stained positively for thyroglobulinand cytokeratin 7 and was negative for cytokeratin20, estrogen receptor, and progesteronereceptor. No nuclear staining with beta-cateninwas found.Patient 2. A 34-year-old woman with a history ofFAP was found to have an enlarged thyroid glandon routine physical examination. In 1992, thepatient had undergone a proctocolectomy and excisionof an abdominal wall desmoid tumor; desmoidsoccur in up to 10% of FAP patients and area manifestation of Gardner’s syndrome. 5 The desmoidwas also treated with adjuvant radiation. In1998, the desmoid tumor recurred in the pelvisand was treated with chemotherapy. In 1999, thepatient was diagnosed with duodenal tubularadenomas. Her paternal grandmother was the indexcase of FAP.Physical examination revealed a 2-cm, smoothdominant nodule of the right thyroid lobe andvague nodularity of the left thyroid lobe. Examinationof the larynx revealed normal mobile vocalcords. Ultrasound demonstrated three nodules inthe right lobe and two smaller nodules in the leftFIGURE 1. The variegated histologic appearance of the cribriform-morular variant. This sporadic case (patient 1) displays cribriform(upper left), papillary (upper right), and hyalinized areas (lower left). Interspersed islands of squamoid and spindle cells (mainly spindlecells in this case) known as morules were also seen (delineated by the arrows; lower right). [Color figure can be viewed in the onlineissue, which is available at www.interscience.wiley.com.]472 Cribriform-Morular Variant of Papillary Cancer HEAD & NECK—DOI 10.1002/hed May 2006
lobe. The most suspicious nodule was located inthe middle of the right thyroid lobe, had coarse,punctuate calcifications, and measured 1.6 cm indiameter. FNA cytology under ultrasonographicguidance strongly suggested PTC. The patientunderwent a total thyroidectomy and had anuneventful postoperative recovery.The final pathology revealed a 2.3-cm PTClocated in the right thyroid lobe. The tumor wasdescribed as containing the ‘cribriform-morularvariant’ of PTC (Figure 2). Although the tumorwas well encapsulated and had no extrathyroidalextension, there was evidence of focal capsuleinvasion. No vascular invasion was identified. Ofinterest, the papillary carcinoma was multifocalwith three additional foci of the ‘cribriform-morularvariant’ ranging from 0.17 to 0.8 cm, located inboth thyroid lobes. The tumor was positive for thyroglobulinand cytokeratin 7 and was negative forcytokeratin 20. The tumor also showed diffuseaberrant nuclear staining for beta-catenin, whereasthe adjacent normal thyroid showed a membranousstaining pattern (Figure 3). In addition, there wasstrong and diffuse nuclear positivity for both estrogenand progesterone receptors.DISCUSSIONIn 1968, the relationship between FAP and thyroidcarcinoma was first suggested. 6 Although theincidence of PTC in patients with FAP is rare at1% to 2%, the relative risk for thyroid carcinomain patients with FAP younger than 35 years of ageis estimated at 160 times that of the general population.2The cribriform-morular variant of papillarycancer of the thyroid is often associated with FAP,as was seen in our second patient. Clinically, thisentity has a female predominance, is multifocal,and tends to occur in patients under the age of30. 1,2,4,7–9 Histologically, this variant has beendescribed as having distinct features, includingan intricate blending of cribriform, trabecular,solid, follicular, morular, and papillary architecture.1,3,8 The uncharacteristic cribriform growthpattern can mislead the pathologist into diagnos-FIGURE 2. Histopathologic features of the cribriform-morular variant (CMV) in case 2. The tumor typically shows mixed architecturalfeatures with cribriform structures (upper left) and an intricate blending of empty follicles and papillae (upper right). Island of squamoidand spindle cells (morule delineated by arrows) shows the typical biotin-rich homogeneous nuclear inclusion also known as peculiarnuclear clearing (lower left). The nuclei are often pseudostratified and resemble those seen in papillary carcinoma, columnar cell variant,leading to the misdiagnosis of the latter variant that can be much more aggressive than CMV (lower right). [Color figure can beviewed in the online issue, which is available at www.interscience.wiley.com.]Cribriform-Morular Variant of Papillary Cancer HEAD & NECK—DOI 10.1002/hed May 2006 473
Page 1: CASE REPORTDennis H. Kraus, MD, Sec
Page 5 and 6: patient without a germline APC muta

cribriform-morular variant of papillary thyroid carcinoma

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