Br. J. Surg. Vol. 62 (1975) 205-206
Cystic thyroid nodules M I C H A E L K . G . M A A N D G . B. O N G * SUMMARY
Among 300 putients with thyroid nodules subjected to N needle drill biopsy, 62 were foirnd to contain cystic lesions. Analysis of these 62 cases showed that in 17 the swelling had completely disappeared after the biopsy. The remaining 45 had residual or recurrent swellings. Operative treatment was carried out in 35, which consisted of 28 (80 per cent) nodular goitres, 6 (17.1 per cent) adenomas and 1 (2.9 per cent) carcinoma.
ABOUT15 per cent of all thyroid nodules are cystic (Crile, 1966). The contents may vary from thick brownish colloid material to thin pale fluid. Clinically they present as solitary nodules either of recent onset and rapid growth or with a history of long duration with little fluctuation in size. Regardless of the mode of development, these cystic nodules are usually medium-sized with a diameter of about 2-5 cm and hard in consistency. They invariably show poor uptake of radioactive l2in the thyroid scan. Hence they stay high on the list for operative treatment because of the risk of malignancy. However, when the nodules are excised the majority of them turn out to be benign lesions. There is a paucity of reports in the literature on the incidence ofcarcinoma in cystic thyroid nodules. Preoperative needle biopsy is still a controversial practice and performed only in a selected group of patients. We set out to study the usefulness of such a procedure in the management of thyroid cyst and in obtaining early histological diagnosis. Materials and methods I n the past 34 years 300 drill biopsies of the thyroid gland have been performed in the Surgical Thyroid Clinic, University of Hong Kong. Patients selected for study included those presenting with either a solitary nodule or a multinodular swelling with poor radioactive iodine uptake in the scan. A high speed pneumatic drill was used. It has a needle of 1.5 mm internal diameter and is driven by compressed air at 5 kg/cm2. Under local anaesthesia a small skin incision was made and the needle was inserted into the centre of the nodule. After it had penetrated the thyroid capsule, it was disconnected from the machine and withdrawn with mild suction. Whenever fluid was aspirated an attempt was always made to empty all the contents by gentle pressure on the gland. The fluid was measured and sent for cytological study. The incision was then covered with an Elastoplast dressing and the patient was discharged. Of the 300 patients studied, 62 were found to have cystic lesions containing fluid of various character and quantity. There was thin yellowish fluid in 10, dark
brownish fluid in 34 and thick colloid material in 18 (Table Z). The amount ranged from 1 to 60 ml with an average of 8 ml. These 62 patients were followed up regularly in the Thyroid Clinic. In 17 (27.4 per cent) the swelling completely disappeared and no further surgical intervention was indicated. However, they were all examined on a monthly basis in case of further development. Thirty-five (56.5 per cent) of the 62 patients were subsequently operated upon because of recurrent or residual swelling. Of these, 28 (80 per cent) were nodular goitres, 6 (17.1 per cent) were adenomas and only 1 carcinoma (Table Z I ) . The remaining 10 patients had some residual swelling in the neck but they refused operative treatment. However, they have been followed up for periods of 2 months to 34 years and are all in good health with no signs of malignancy. Table I : TYPE OF FLUID ASPlRATED IN 62 PATIENTS Type: Thin yellow fluid No. o f cases: 10 Thick colloid material 18 Dark brownish fluid 34 Table 11: RESULTS OF DRILL BIOPSY IN 62 PATIENTS Result
Nodule subsided Residual swelling with no operation Residual or recurrent swelling with operation Nodular goitre Adenoma Papillary carcinoma
No. of cases 17 10
35 28 (80%) 6 (17-1x,)
1 (2%)
Discussion Needle biopsy of the thyroid gland has long been a controversial practice. It is only occasionally performed in apparently benign lesions because of the potential risk of tumour dissemination. Since the introduction of the high speed pneumatic drill, Deeley and Pollock (1966) have successfully used it to biopsy enlarged lymph nodes, lung, thyroid, breast and various soft tissue tumours. Risk of cancer dissemination was shown by Burn et al. (1968) to be low. We have therefore used the drill to biopsy 300 patients with thyroid swellings. Patients selected for the study included those presenting with a solitary nodule, a multi-nodular swelling with a ‘cold’ area in the thyroid scan or non-toxic diffuse swellings. One of the * Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong. 205
Michael K. G. Ma and G. B. Ong aims of this study was to evaluate the management of a cystic thyroid nodule by aspiration. If such cysts can be treated by simply emptying the contents without risk of leaving behind a carcinoma, then a large number of unnecessary operations can be avoided. Sixty-two patients in this series were found to have cystic thyroid nodules. The cysts contained fluid of various quality and quantity which was aspirated by a high speed pneumatic drill. The character of the fluid had no significant bearing on the nature of the lesion. In 17 the swelling completely subsided with no recurrence. We chose to postpone operative treatment of these patients and to follow them up at monthly intervals. In 10 there were some residual swelling or recurrence after the drill biopsy but the patients refused operation. Both groups of patients have now been followed up for periods of 2 months to 3: years. S o far none of them has shown any signs that warrant an early exploration. In the remaining 35 of the 62 patients operation was carried out, the indication being residual or recurrent swelling. Of these, 28 (80 per cent) had nodular goitre, 6 (17.1 per cent) had adenoma and only 1 patient (2.9 per cent) had a papillary carcinoma. If we assume the cystic lesions that disappeared after aspiration to be benign, then
206
the incidence of carcinoma in cystic thyroid nodules was 1.9 per cent. Crile (1966) treated 58 cases of thyroid cysts with needle aspiration and encountered no malignant tumour. It would appear that such cystic lesions of the thyroid gland, whether solitary or multinodular, and which routinely show poor uptake of radioactive iodine in the scan, could well be safely managed by this simple method. A preoperative drill biopsy would serve as both a diagnostic and therapeutic procedure. It is safe and was well tolerated by our 62 patients without any complication. Also, if a careful cytological examination were done on every sample of cyst contents, there should be no difficulty in diagnosing the small proportion of cases which truly warrant an operation. References and MALAKER K. (1968) Drill biopsy and dissemination of cancer. Br. J . Suvg. 55, 628-631. CRILE G. jun. (1966) Treatment of thyroid cyst by aspiration. Surgery 59, 210-212. DEELEY T. J. and POLLOCK D. J. (1966) Experience with a high speed pneumatic drill biopsy machine. Br. J . Cancer 20, 442-447. B U R N J. I., DEELEY T. J.
Cystic thyroid nodules M I C H A E L K . G . M A A N D G . B. O N G * SUMMARY
Among 300 putients with thyroid nodules subjected to N needle drill biopsy, 62 were foirnd to contain cystic lesions. Analysis of these 62 cases showed that in 17 the swelling had completely disappeared after the biopsy. The remaining 45 had residual or recurrent swellings. Operative treatment was carried out in 35, which consisted of 28 (80 per cent) nodular goitres, 6 (17.1 per cent) adenomas and 1 (2.9 per cent) carcinoma.
ABOUT15 per cent of all thyroid nodules are cystic (Crile, 1966). The contents may vary from thick brownish colloid material to thin pale fluid. Clinically they present as solitary nodules either of recent onset and rapid growth or with a history of long duration with little fluctuation in size. Regardless of the mode of development, these cystic nodules are usually medium-sized with a diameter of about 2-5 cm and hard in consistency. They invariably show poor uptake of radioactive l2in the thyroid scan. Hence they stay high on the list for operative treatment because of the risk of malignancy. However, when the nodules are excised the majority of them turn out to be benign lesions. There is a paucity of reports in the literature on the incidence ofcarcinoma in cystic thyroid nodules. Preoperative needle biopsy is still a controversial practice and performed only in a selected group of patients. We set out to study the usefulness of such a procedure in the management of thyroid cyst and in obtaining early histological diagnosis. Materials and methods I n the past 34 years 300 drill biopsies of the thyroid gland have been performed in the Surgical Thyroid Clinic, University of Hong Kong. Patients selected for study included those presenting with either a solitary nodule or a multinodular swelling with poor radioactive iodine uptake in the scan. A high speed pneumatic drill was used. It has a needle of 1.5 mm internal diameter and is driven by compressed air at 5 kg/cm2. Under local anaesthesia a small skin incision was made and the needle was inserted into the centre of the nodule. After it had penetrated the thyroid capsule, it was disconnected from the machine and withdrawn with mild suction. Whenever fluid was aspirated an attempt was always made to empty all the contents by gentle pressure on the gland. The fluid was measured and sent for cytological study. The incision was then covered with an Elastoplast dressing and the patient was discharged. Of the 300 patients studied, 62 were found to have cystic lesions containing fluid of various character and quantity. There was thin yellowish fluid in 10, dark
brownish fluid in 34 and thick colloid material in 18 (Table Z). The amount ranged from 1 to 60 ml with an average of 8 ml. These 62 patients were followed up regularly in the Thyroid Clinic. In 17 (27.4 per cent) the swelling completely disappeared and no further surgical intervention was indicated. However, they were all examined on a monthly basis in case of further development. Thirty-five (56.5 per cent) of the 62 patients were subsequently operated upon because of recurrent or residual swelling. Of these, 28 (80 per cent) were nodular goitres, 6 (17.1 per cent) were adenomas and only 1 carcinoma (Table Z I ) . The remaining 10 patients had some residual swelling in the neck but they refused operative treatment. However, they have been followed up for periods of 2 months to 34 years and are all in good health with no signs of malignancy. Table I : TYPE OF FLUID ASPlRATED IN 62 PATIENTS Type: Thin yellow fluid No. o f cases: 10 Thick colloid material 18 Dark brownish fluid 34 Table 11: RESULTS OF DRILL BIOPSY IN 62 PATIENTS Result
Nodule subsided Residual swelling with no operation Residual or recurrent swelling with operation Nodular goitre Adenoma Papillary carcinoma
No. of cases 17 10
35 28 (80%) 6 (17-1x,)
1 (2%)
Discussion Needle biopsy of the thyroid gland has long been a controversial practice. It is only occasionally performed in apparently benign lesions because of the potential risk of tumour dissemination. Since the introduction of the high speed pneumatic drill, Deeley and Pollock (1966) have successfully used it to biopsy enlarged lymph nodes, lung, thyroid, breast and various soft tissue tumours. Risk of cancer dissemination was shown by Burn et al. (1968) to be low. We have therefore used the drill to biopsy 300 patients with thyroid swellings. Patients selected for the study included those presenting with a solitary nodule, a multi-nodular swelling with a ‘cold’ area in the thyroid scan or non-toxic diffuse swellings. One of the * Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong. 205
Michael K. G. Ma and G. B. Ong aims of this study was to evaluate the management of a cystic thyroid nodule by aspiration. If such cysts can be treated by simply emptying the contents without risk of leaving behind a carcinoma, then a large number of unnecessary operations can be avoided. Sixty-two patients in this series were found to have cystic thyroid nodules. The cysts contained fluid of various quality and quantity which was aspirated by a high speed pneumatic drill. The character of the fluid had no significant bearing on the nature of the lesion. In 17 the swelling completely subsided with no recurrence. We chose to postpone operative treatment of these patients and to follow them up at monthly intervals. In 10 there were some residual swelling or recurrence after the drill biopsy but the patients refused operation. Both groups of patients have now been followed up for periods of 2 months to 3: years. S o far none of them has shown any signs that warrant an early exploration. In the remaining 35 of the 62 patients operation was carried out, the indication being residual or recurrent swelling. Of these, 28 (80 per cent) had nodular goitre, 6 (17.1 per cent) had adenoma and only 1 patient (2.9 per cent) had a papillary carcinoma. If we assume the cystic lesions that disappeared after aspiration to be benign, then
206
the incidence of carcinoma in cystic thyroid nodules was 1.9 per cent. Crile (1966) treated 58 cases of thyroid cysts with needle aspiration and encountered no malignant tumour. It would appear that such cystic lesions of the thyroid gland, whether solitary or multinodular, and which routinely show poor uptake of radioactive iodine in the scan, could well be safely managed by this simple method. A preoperative drill biopsy would serve as both a diagnostic and therapeutic procedure. It is safe and was well tolerated by our 62 patients without any complication. Also, if a careful cytological examination were done on every sample of cyst contents, there should be no difficulty in diagnosing the small proportion of cases which truly warrant an operation. References and MALAKER K. (1968) Drill biopsy and dissemination of cancer. Br. J . Suvg. 55, 628-631. CRILE G. jun. (1966) Treatment of thyroid cyst by aspiration. Surgery 59, 210-212. DEELEY T. J. and POLLOCK D. J. (1966) Experience with a high speed pneumatic drill biopsy machine. Br. J . Cancer 20, 442-447. B U R N J. I., DEELEY T. J.
