ClinicalRadiology (1991) 43, 213 214
Case Report: Cystic Lymph Node Metastasis from Occult Thyroid Carcinoma: A Sonographic Mimic of a Branchial Cleft Cyst C. F. L O U G H R A N
X-Ray Department, Maccles[ieM District General Hospital, Macclesfield, Cheshire A case is described in which a soft tissue mass in the neck thought, both clinically and sonographically, to be a branchial cyst was later shown to be a cystic lymph node metastasis from an occult thyroid carcinoma. L o u g h r a n , C . F . (1991). Clinical Radiology 43, 2 1 3 - 2 1 4 . Case Report: Cystic Lymph Node Metastasis Sonographic Mimic of a Branchial Cleft Cyst
from
Occult
Thyroid
Carcinoma:
A
CASE REPORT A 19-year-old male presented with a painless swelling of the right side of the neck which he had noticed for a week. On examination a smooth swelling was palpable in the neck, approximately 3 cm x 2 cm in size. No further masses were palpable and the thyroid in particular appeared normal. Clinically, this was thought to be a branchial cyst. Ultrasound of the neck (5 MHz linear array) confirmed the presence of an egg shaped cystic structure within the neck. This lay anterior to the common carotid artery and jugular vein and posterior to the sternocleidomastoid. The cyst had a smooth external surface but the inner lining was thickened and irregular. Occasional incomplete septa were noted within it. There was good through transmission of sound with well marked distal acoustic enhancement (Fig. 1). No other masses were shown in the neck and the thyroid in particular appeared normal. Despite the slightly atypical sonographic appearance the lesion was considered most likely to be a branchial cyst in view of its typical location, shape, size and clinical presentation. The cyst was removed without complication. Histologically it consisted of multiple loculi lined by lymphoid tissue and, in certain areas, by compressed thyroid tissue. Occasional loculi contained areas of proliferating papillary thyroid tissue. The changes
Fig. 2 - Thyroid isotope scan (80 MBq 99mTc).This scan was interpreted as normal.
were those of a papillary carcinoma of the thyroid. A radionuclide thyroid scan was undertaken (80 MBq 99mTc). This was regarded as normal (Fig. 2). He later underwent a total thyroideetomy. The specimen contained a papillary carcinoma of the thyroid isthmus which measured 1 cm in diameter. It had broken through the capsule of the gland and infiltrated the local lymphatic tissue producing multiple small lymph node metastases. The right and left lobes of the thyroid were normal. He made a successful post-operative recovery and is currently maintained on 40/zg of Tertroxin daily.
DISCUSSION
Fig. 1 - A longitudinal oblique scan of the lateral neck cyst. Note the oval shape, slightly irregular inner wall and good through transmission of sound with distal enhancement. Occasional, incomplete septae are shown. Correspondence to: C. F. Loughran, X-ray Department, Macclesfield District General Hospital, Victoria Road, Macclesfield, Cheshire SKI0 3BL.
O c c u l t p a p i l l a r y c a r c i n o m a o f t h e t h y r o i d is n o t a n u n c o m m o n t h y r o i d t u m o u r . O f 550 p a t i e n t s w i t h p a p i l l a r y cell c a r c i n o m a o p e r a t e d o n a t t h e M a y o Clinic, 137 ( 4 0 % ) w e r e classified as o c c u l t c a r c i n o m a s , i.e. t h o s e less t h a n 1.5 c m i n size ( H u b e r t et al., 1980). S u c h t u m o u r s a r e o f t e n i m p a l p a b l e b u t a p p r o x i m a t e l y 4 0 % will h a v e a s s o c i a t e d l y m p h n o d e m e t a s t a s e s a n d t h e s e a r e frequently the cause of presentation. Papillary carcinoma a c c o u n t s f o r 7 0 % o f all t h y r o i d t u m o u r s f o u n d in p a t i e n t s
214
CLINICAL RADIOLOGY
aged 40 years or less. Furthermore, in this age group nodal involvement is particularly likely to occur (Mazzaferri et al., 1977). The c o m m o n e s t cyst to arise laterally within the neck is a branchial cleft cyst, a developmental a n o m a l y from the second branchial cleft. This usually presents in the third decade as a soft tissue mass arising at any point in the embryological tract extending f r o m the tonsillar fossa o f the o r o p h a r y n x to the supraclavicular region o f the neck. Sonographically, branchial cleft cysts are characteristically echo free lesions with a s m o o t h inner wall producing good distal enhancement. However, there are exceptions to this typical appearance: multiloculated branchial cysts do occur (Howie and Proops, 1982) and the wall m a y thicken and become irregular should the cyst become infected (Ingoldby, 1985). The wall o f an infected cyst m a y enhance at C T following intravenous contrast enhancement (Kreipke and Lingeman, 1984). The attenuation values m a y also change as the protein content of the cyst increases. Metastatic lymph nodes m a y mimic lesions o f the branchial cleft. Papillary thyroid carcinoma and primary tumours o f the bronchus, genito-urinary tract and gastrointestinal tract m a y rarely produce cystic metastases. Characteristically these cyst like masses are rounded, not oval, as in this case (Som, 1987). Other diagnostic considerations are cystic hygromas, true thyroid and parathyroid cysts, dermoids, cervical thymic cysts, cystic neuromas, and choristomas (Som et al., 1985). Wallace and Betsill (1984), described four cases o f thyroid carcinoma presenting as lateral neck cysts. In one the cyst was a direct extension from a papillary thyroid carcinoma. O f the remaining examples two were due to metastases f r o m occult thyroid carcinomas. Ultrasonically, two o f the cases were cystic in nature. The demonstration o f a lateral neck cyst should always p r o m p t a careful examination o f the thyroid with ultrasound, preferably with a high resolution transducer. Transducers o f at least 7.5 M H z , and possibly 10 M H z (James and Charboneau, 1985) should be used to examine
the thryoid. A 10 M H z transducer has a lateral resolution o f 1-2 m m which should enhance detection of such small tumours. Failure to recognize an occult thyroid t u m o u r can erroneously suggest that a lateral neck cyst has no connection with the thyroid. Scintigraphy has a limited diagnostic role in the detection o f small lesions within the thyroid. Almost 10% o f all tumours in Mazzaferri et al.'s review (1977) were not detected at scintigraphy - a finding confirmed by others (Bartold et al., 1986). I f a lesion is detected at ultrasound then'fine needle diagnostic aspiration m a y help rule out underlying thyroid malignancy. Acknowledgements:I thank Mr R. W. K. Neill, Consultant Surgeon, for permission to report this case.
REFERENCES
Bartold, KP, Abghari, R & Sangi,VB (1986). Uncommon presentations of thyroid carcinoma. Clinical Nuclear Medicine, 11, 786 787. Howie, AJ & Proops, DW (1982). The definition of branchial cysts, sinuses and fistulae. Clinical Otolaryngology, 7, 51 57. Hubert, JP, Kiernan, PD, Behars, OH, McConahey, WM & Woolner, LB (1980). Occult papillary carcinoma of the thyroid Archives of Surgery, 115, 394-398. Ingoldby, CJH (1985). Unusual presentations of branchial cysts: a trap for the unwary. Annals of the Royal College of Surgeons of England, 67, 175 176. James, EM & Charboneau, JW (1985). High frequency (10 MHz) thyroid ultrasonography. Seminars in Ultrasound, CT and MR, 6, 294 304. Kreipke, DL & Lingeman, RE (1984). Cross sectional imaging (CT, NMR) of branchial cysts: report of three cases. Journal of Computer Assisted Tomography, 8, 114 116. Mazzaferri, EL, Young, RL, Oertel, JE, Kemmererm, WT & Page, CP (1977). Papillary thyroid carcinoma: the impact of therapy in 576 patients. Medicine, 56, 171-195. Som, PM (1987). Lymph nodes of the neck. Radiology, 165, 593-600. Sore, PM, Sacher, M. Lanzieri, CF, Solodnik, P, Cohen, B, Reede, DL et al. (1985). Parenchymal cysts of the lower neck. Radiology, 157, 399-406. Wallace, MP & Betsill, WL (1984). Papillary carcinoma of the thyroid gland seen as lateral neck cyst. Archives ofOtolaryngology, ll0, 408 411.
Case Report: Cystic Lymph Node Metastasis from Occult Thyroid Carcinoma: A Sonographic Mimic of a Branchial Cleft Cyst C. F. L O U G H R A N
X-Ray Department, Maccles[ieM District General Hospital, Macclesfield, Cheshire A case is described in which a soft tissue mass in the neck thought, both clinically and sonographically, to be a branchial cyst was later shown to be a cystic lymph node metastasis from an occult thyroid carcinoma. L o u g h r a n , C . F . (1991). Clinical Radiology 43, 2 1 3 - 2 1 4 . Case Report: Cystic Lymph Node Metastasis Sonographic Mimic of a Branchial Cleft Cyst
from
Occult
Thyroid
Carcinoma:
A
CASE REPORT A 19-year-old male presented with a painless swelling of the right side of the neck which he had noticed for a week. On examination a smooth swelling was palpable in the neck, approximately 3 cm x 2 cm in size. No further masses were palpable and the thyroid in particular appeared normal. Clinically, this was thought to be a branchial cyst. Ultrasound of the neck (5 MHz linear array) confirmed the presence of an egg shaped cystic structure within the neck. This lay anterior to the common carotid artery and jugular vein and posterior to the sternocleidomastoid. The cyst had a smooth external surface but the inner lining was thickened and irregular. Occasional incomplete septa were noted within it. There was good through transmission of sound with well marked distal acoustic enhancement (Fig. 1). No other masses were shown in the neck and the thyroid in particular appeared normal. Despite the slightly atypical sonographic appearance the lesion was considered most likely to be a branchial cyst in view of its typical location, shape, size and clinical presentation. The cyst was removed without complication. Histologically it consisted of multiple loculi lined by lymphoid tissue and, in certain areas, by compressed thyroid tissue. Occasional loculi contained areas of proliferating papillary thyroid tissue. The changes
Fig. 2 - Thyroid isotope scan (80 MBq 99mTc).This scan was interpreted as normal.
were those of a papillary carcinoma of the thyroid. A radionuclide thyroid scan was undertaken (80 MBq 99mTc). This was regarded as normal (Fig. 2). He later underwent a total thyroideetomy. The specimen contained a papillary carcinoma of the thyroid isthmus which measured 1 cm in diameter. It had broken through the capsule of the gland and infiltrated the local lymphatic tissue producing multiple small lymph node metastases. The right and left lobes of the thyroid were normal. He made a successful post-operative recovery and is currently maintained on 40/zg of Tertroxin daily.
DISCUSSION
Fig. 1 - A longitudinal oblique scan of the lateral neck cyst. Note the oval shape, slightly irregular inner wall and good through transmission of sound with distal enhancement. Occasional, incomplete septae are shown. Correspondence to: C. F. Loughran, X-ray Department, Macclesfield District General Hospital, Victoria Road, Macclesfield, Cheshire SKI0 3BL.
O c c u l t p a p i l l a r y c a r c i n o m a o f t h e t h y r o i d is n o t a n u n c o m m o n t h y r o i d t u m o u r . O f 550 p a t i e n t s w i t h p a p i l l a r y cell c a r c i n o m a o p e r a t e d o n a t t h e M a y o Clinic, 137 ( 4 0 % ) w e r e classified as o c c u l t c a r c i n o m a s , i.e. t h o s e less t h a n 1.5 c m i n size ( H u b e r t et al., 1980). S u c h t u m o u r s a r e o f t e n i m p a l p a b l e b u t a p p r o x i m a t e l y 4 0 % will h a v e a s s o c i a t e d l y m p h n o d e m e t a s t a s e s a n d t h e s e a r e frequently the cause of presentation. Papillary carcinoma a c c o u n t s f o r 7 0 % o f all t h y r o i d t u m o u r s f o u n d in p a t i e n t s
214
CLINICAL RADIOLOGY
aged 40 years or less. Furthermore, in this age group nodal involvement is particularly likely to occur (Mazzaferri et al., 1977). The c o m m o n e s t cyst to arise laterally within the neck is a branchial cleft cyst, a developmental a n o m a l y from the second branchial cleft. This usually presents in the third decade as a soft tissue mass arising at any point in the embryological tract extending f r o m the tonsillar fossa o f the o r o p h a r y n x to the supraclavicular region o f the neck. Sonographically, branchial cleft cysts are characteristically echo free lesions with a s m o o t h inner wall producing good distal enhancement. However, there are exceptions to this typical appearance: multiloculated branchial cysts do occur (Howie and Proops, 1982) and the wall m a y thicken and become irregular should the cyst become infected (Ingoldby, 1985). The wall o f an infected cyst m a y enhance at C T following intravenous contrast enhancement (Kreipke and Lingeman, 1984). The attenuation values m a y also change as the protein content of the cyst increases. Metastatic lymph nodes m a y mimic lesions o f the branchial cleft. Papillary thyroid carcinoma and primary tumours o f the bronchus, genito-urinary tract and gastrointestinal tract m a y rarely produce cystic metastases. Characteristically these cyst like masses are rounded, not oval, as in this case (Som, 1987). Other diagnostic considerations are cystic hygromas, true thyroid and parathyroid cysts, dermoids, cervical thymic cysts, cystic neuromas, and choristomas (Som et al., 1985). Wallace and Betsill (1984), described four cases o f thyroid carcinoma presenting as lateral neck cysts. In one the cyst was a direct extension from a papillary thyroid carcinoma. O f the remaining examples two were due to metastases f r o m occult thyroid carcinomas. Ultrasonically, two o f the cases were cystic in nature. The demonstration o f a lateral neck cyst should always p r o m p t a careful examination o f the thyroid with ultrasound, preferably with a high resolution transducer. Transducers o f at least 7.5 M H z , and possibly 10 M H z (James and Charboneau, 1985) should be used to examine
the thryoid. A 10 M H z transducer has a lateral resolution o f 1-2 m m which should enhance detection of such small tumours. Failure to recognize an occult thyroid t u m o u r can erroneously suggest that a lateral neck cyst has no connection with the thyroid. Scintigraphy has a limited diagnostic role in the detection o f small lesions within the thyroid. Almost 10% o f all tumours in Mazzaferri et al.'s review (1977) were not detected at scintigraphy - a finding confirmed by others (Bartold et al., 1986). I f a lesion is detected at ultrasound then'fine needle diagnostic aspiration m a y help rule out underlying thyroid malignancy. Acknowledgements:I thank Mr R. W. K. Neill, Consultant Surgeon, for permission to report this case.
REFERENCES
Bartold, KP, Abghari, R & Sangi,VB (1986). Uncommon presentations of thyroid carcinoma. Clinical Nuclear Medicine, 11, 786 787. Howie, AJ & Proops, DW (1982). The definition of branchial cysts, sinuses and fistulae. Clinical Otolaryngology, 7, 51 57. Hubert, JP, Kiernan, PD, Behars, OH, McConahey, WM & Woolner, LB (1980). Occult papillary carcinoma of the thyroid Archives of Surgery, 115, 394-398. Ingoldby, CJH (1985). Unusual presentations of branchial cysts: a trap for the unwary. Annals of the Royal College of Surgeons of England, 67, 175 176. James, EM & Charboneau, JW (1985). High frequency (10 MHz) thyroid ultrasonography. Seminars in Ultrasound, CT and MR, 6, 294 304. Kreipke, DL & Lingeman, RE (1984). Cross sectional imaging (CT, NMR) of branchial cysts: report of three cases. Journal of Computer Assisted Tomography, 8, 114 116. Mazzaferri, EL, Young, RL, Oertel, JE, Kemmererm, WT & Page, CP (1977). Papillary thyroid carcinoma: the impact of therapy in 576 patients. Medicine, 56, 171-195. Som, PM (1987). Lymph nodes of the neck. Radiology, 165, 593-600. Sore, PM, Sacher, M. Lanzieri, CF, Solodnik, P, Cohen, B, Reede, DL et al. (1985). Parenchymal cysts of the lower neck. Radiology, 157, 399-406. Wallace, MP & Betsill, WL (1984). Papillary carcinoma of the thyroid gland seen as lateral neck cyst. Archives ofOtolaryngology, ll0, 408 411.
