Radiology Quiz Case 1

CLINICAL PROBLEM SOLVING: RADIOLOGY SECTION EDITOR: C. DOUGLAS PHILLIPS, MD

Radiology Quiz Case 1 Stephanie S. Colello, AB; Michael J. Cunningham, MD; Caroline D. Robson, MBChB; Lisa A. Teot, MD; Children’s Hospital Boston (Ms Colello and Drs Cunningham, Robson, and Teot) and Harvard Medical School (Drs Cunningham, Robson, and Teot), Boston, Massachusetts

A

5-WEEK-OLD BOY PRESENTED WITH A MASS on the right side of his neck noted immediately at birth, with no subsequent reported change in size or shape. He had no respiratory distress, breastfeeding difficulties, or systemic infectious or inflammatory manifestations. The child was born full term by cesarean delivery following an uncomplicated pregnancy with normal results on fetal ultrasonography (US). On physical examination, the infant appeared healthy, was breathing comfortably, and had a normal cry. The

Figure 1.

mass on the right side of his neck measured approximately 2 cm in diameter, was nontender, somewhat compressible but firm, with no discoloration of the overlying skin. Findings from the otolaryngology assessment were otherwise normal with the exception of the laryngeal examination, which revealed an immobile right true vocal fold and compensatory movement of the left true vocal fold. Cervical US demonstrated a heterogeneous mass that was inseparable from the right lobe of the thyroid gland (Figure 1). The mass consisted of several complex cystic as well as solid components with some vascularity. Cervical magnetic resonance imaging (MRI) confirmed a predominantly right-sided 3⫻4⫻ 3-cm mass containing both solid and cystic components with heterogeneous enhancement (Figure 2 and Figure 3). The superior aspect of the mass extended to the level of the submandibular triangle, and the inferior aspect extended to the supraclavicular space. The mass abutted but did not compress the trachea. Results from additional tests, including a complete blood cell count, thyroid function studies, and tests for ␣-fetoprotein and ␤-human chorionic gonadotropin tumor markers, were all normal. Complete mass excision, including a hemithyroidectomy, was performed. What is your diagnosis?

Figure 3.

Figure 2.

JAMA OTOLARYNGOL HEAD NECK SURG/ VOL 139 (NO. 6), JUNE 2013 643

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Radiology Quiz Case 1: Diagnosis Diagnosis: Congenital cervical teratoma

“Teratoma” is derived from the Greek term meaning “monstrous tumor,” demonstrative of the often dramatic appearance of this lesion. Teratomas are believed to arise secondary to developmental errors in totipotential germ cells and are composed of elements from all 3 germ layers—the endoderm, mesoderm, and ectoderm.1 The types and distribution of tissues result in a heterogeneous appearance, both within and between tumors. The composite tissues are often foreign to the region of the body in which the lesion is located.2 Teratomas may be classified as mature, immature, or malignant. Mature teratomas are composed of mature elements and are characteristically benign. Immature teratomas contain a combination of mature and immature tissue types, the latter often comprised of primitive neuroectodermal elements, and have malignant potential.2 Malignant teratomas are characterized by the presence of malignant neural or somatic components, or 1 or more malignant germ cell elements (yolk sac tumor, choriocarcinoma, embryonal carcinoma, or germinoma). As in other sites, most of the cervical teratomas in newborns and infants are mature and, irrespective of the presence of immature elements, usually behave in a benign manner.3-5 Malignant head and neck teratomas in children are extremely rare.1,5 In contrast, teratomas in older children and adults are more likely to follow a malignant course, even when overtly malignant elements are not identified. Teratomas most commonly arise in the sacrococcygeal region. Cervical teratomas are comparatively infrequent, accounting for approximately 3% of all neonatal teratomas,6 with a quoted prevalence of 1 in 80 000 births.2 Prenatal US may detect cervical teratoma as a heterogeneous solid and cystic neck mass that can be further characterized by fetal MRI, which is useful in further characterizing the tumor and in demonstrating associated congenital high airway obstruction syndrome (CHAOS) in 20% to 50% of fetal teratoma cases.3 CHAOS results from partial or complete mass obstruction of the upper aerodigestive tract. Tracheal obstruction results in fetal lung congestion with secondary diaphragm flattening or eversion. Decreased fetal swallowing owing to compression of the esophagus leads to maternal polyhydramnios.7 In addition to cervical teratoma, comparatively less frequent causes of CHAOS include lymphatic vascular malformation and foregut duplication cysts. An ex utero intrapartum treatment procedure may be indicated to secure the fetal airway if clinically significant obstruction is predicted prenatally. Most cervical teratomas are detected following birth on neonatal examination. A large, firm, multinodular neck mass with both cystic and solid properties is characteristic. An anterolateral cervical presentation is most common. As is the case prenatally, the size and location of the mass may cause obstruction of the aerodigestive tract with subsequent respiratory distress and feeding

difficulty. Torticollis may also occur secondary to mass effect. Children with associated recurrent laryngeal nerve involvement are at further risk for aspiration, vocal dysfunction, and breathing difficulties. In contrast to vascular malformations, the skin covering the mass is usually normal and not discolored.2 Elevated levels of ␣-fetoprotein and ␤-human chorionic gonadotropin are indicative of potential malignant lesion.8 Radiographic evaluation includes prenatal and postnatal US, computed tomography and MRI. Ultrasonography can document both solid and cystic components, and color Doppler US may determine vascularity. 4 Ultrasonography may also provide evidence of calcification through mixed echogenicity with acoustic shadowing.2 Computed imaging characteristically reveals wellencapsulated, heterogeneous lesions with speckled areas of calcification and sometimes low-density fatty components. The finding of a heterogeneous neck mass with calcifications and absence of the ipsilateral thyroid lobe or splaying of thyroid tissue around the tumor is particularly diagnostic of cervical teratoma.9,10 Computed imaging also provides details of bony remodeling or erosion, particularly for large tumors invading the skull base. Magnetic resonance imaging avoids the use of ionizing radiation, provides excellent soft-tissue characterization, and assesses tumor vascularity; it can also document soft-tissue extension of the mass into the pharynx, cranial fossa, or mediastinum. The differential diagnosis of cervical teratoma includes lymphatic vascular malformation, thyroid gland malignant diseases, rhabdomyosarcoma or alternative softtissue malignant diseases, and, less likely, thymic gland and branchial cleft anomalies. Heterogeneity within the tumor is an important clue to the correct diagnosis. The solid components of the mass rule out the likelihood of lymphatic vascular malformation as well as other congenital cystic developmental lesions, whereas the cystic characteristics argue against thyroid or other soft-tissue malignant diseases. Histopathologic confirmation is eventually necessary. The ideal treatment for cervical teratomas is complete surgical excision. Because the neoplasm may be inseparable from the thyroid gland, partial or complete ipsilateral thyroidectomy may be indicated to completely excise the tumor. Postoperative monitoring for possible hypothyroidism and, less likely, hypoparathyroidism is necessary. Paresis or paralysis of the vagus and recurrent laryngeal nerves is an additional possible surgical complication. Because teratomas are derived from all 3 germ layers, pathologic evaluation typically reveals a heterogeneous, cystic, and solid mass composed of a wide variety of tissue types. The tissues may recapitulate those of welldeveloped organs. The histopathologic features that confirmed this child’s mass to be a mature teratoma included small cystic spaces lined by respiratory, squamous, gastrointestinal and cuboidal epithelium; clusters of thyroid microfollicles; abundant mature neuroglial tissue focally lined by choroid plexus; abundant skeletal muscle;


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haphazardly arrayed smooth muscle; adipose tissue; and scattered islands of cartilage. No immature or malignant elements were identified. Benign thyroid tissue was present at the periphery of the teratoma. With complete resection, recurrence of benign cervical teratomas is rare, and the prognosis is excellent. Malignant teratomas are a greater challenge, often requiring a combination of tumor excision and adjuvant chemotherapy. REFERENCES 1. Chakravarti A, Shashidhar TB, Naglot S, Sahni JK. Head and neck teratomas in children: a case series. Indian J Otolaryngol Head Neck Surg. 2011;63(2):193197. 2. Carr MM, Thorner P, Phillips JH. Congenital teratomas of the head and neck. J Otolaryngol. 1997;26(4):246-252.

3. Martino F, Avila LF, Encinas JL, et al. Teratomas of the neck and mediastinum in children. Pediatr Surg Int. 2006;22(8):627-634. 4. Rahbar R, Vogel A, Myers LB, et al. Fetal surgery in otolaryngology: a new era in the diagnosis and management of fetal airway obstruction because of advances in prenatal imaging. Arch Otolaryngol Head Neck Surg. 2005;131(5):393-398. 5. Thompson LDR, Rosai J, Heffess CS. Primary thyroid teratomas: a clinicopathologic study of 30 cases. Cancer. 2000;88(5):1149-1158. 6. Batra P, Saha A. Congenital cervical teratoma. Indian Pediatr. 2006;43(6):549. 7. Vidaeff AC, Szmuk P, Mastrobattista JM, Rowe TF, Ghelber O. More or less CHAOS: case report and literature review suggesting the existence of a distinct subtype of congenital high airway obstruction syndrome. Ultrasound Obstet Gynecol. 2007; 30(1):114-117. 8. Fichera S, Hackett H, Secola R. Perinatal germ cell tumors: a case report of a cervical teratoma. Adv Neonatal Care. 2010;10(3):133-139. 9. Riedlinger WF, Lack EE, Robson CD, Rahbar R, Nose´ V. Primary thyroid teratomas in children: a report of 11 cases with a proposal of criteria for their diagnosis. Am J Surg Pathol. 2005;29(5):700-706. 10. Robson CD. Imaging of head and neck neoplasms in children. Pediatr Radiol. 2010;40(4):499-509.


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