Primary lymphoma of the thyroid: clinical features, prognostic factors, and results of treatment

A diffuse large B-cell thyroid lymphoma presented as a compressive goiter in a young woman with no evidence of Hashimoto's thyroiditis

Thyroid lymphoma should be suspected in case of rapid enlargement of the thyroid gland even in a young patient with no history of Hashimoto thyroiditis. The confirmation is based on histopathology and immunohistochemistry.

Non-Hodgkin lymphoma of the thyroid in a patient with hyperthyroidism

Primary thyroid lymphoma is incredibly rare with an annual incidence of approximately 2.1 per million persons, accounting for 2% of thyroid malignancies. One of the only known risk factors is autoimmune thyroid disease, specifically Hashimoto’s, although there have been a few cases of thyroid lymphoma associated with Graves’ disease.

Here, we present one such case of a patient with pre-existing hyperthyroidism who developed non-Hodgkin’s lymphoma of the thyroid. The patient initially presented with rapidly progressing right-sided neck swelling. He was clinically and biochemically euthyroid with negative thyroid stimulating immunoglobulin, maintained on methimazole. Biopsy of the thyroid nodule with flow cytometry revealed non-Hodgkin lymphoma. Intervention included radiation therapy.

Radical surgery for primary thyroid lymphoma in a Filipino female: Report of a case and review of literature

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Primary Thyroid Lymphomas are rare tumors that must be suspected in progressively enlarging thyroid masses in the background of Hashimoto’s thyroidits.

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Tissue diagnosis combined with appropriate radiologic imaging may lead to an accurate diagnosis.

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Preoperative diagnosis is ideal to avoid unnecessary surgery due to the availability of effective multimodal treatment with chemoradiotherapy.

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Surgery may be appropriate and effective in a select group of patients but must be combined with adjuvant chemoradiotherapy to achieve favorable outcomes.

Introduction

Primary thyroid lymphomas are rare. They constitute only 2% of all thyroid malignancies. It is important to distinguish it from other tumors of the thyroid due to the marked difference in approach to management. Preoperative diagnostic confirmation is ideal to allow for appropriate therapeutic management, which consists of chemotherapy with or without radiotherapy and to avoid unnecessary surgery. In a select group of patients, surgery may be of benefit to relieve obstructive symptoms and establish diagnosis.

Case presentation

Presented herein is a 48 year old female with a progressively enlarging neck mass previously being treated for Hashimoto’s thyroiditis. Obstructive symptoms and a preoperative diagnosis of anaplastic carcinoma prompted surgical intervention. The patient underwent resection of the tumor with a total thyroidectomy and bilateral neck dissection. Post -operative diagnosis of non Hodgkins diffuse large B cell type of lymphoma was made.

Discussion

Primary thyroid lymphomas are rare tumors that may present similarly with some types of thyroid malignancies. An accurate diagnosis is important because non-surgical treatment options like combination chemotherapy and radiotherapy may be effective while sparing the patient from unnecessary radical surgery.

Conclusion

Primary thyroid lymphoma must be a differential diagnosis in patients presenting with large thyroid tumors in the background of Hashimoto’s thyroiditis. Although chemoradiotherapy is the preferred treatment approach, there is a role for surgery in cases of tumor obstruction and uncertain diagnosis.

Diagnosis and Management of Thyroid Cancer

Thyroid carcinoma, which comprises the majority of endocrine malignancies, has a substantial annual morbidity and mortality based on age and other predisposing factors. Diagnosis of a growing thyroid nodule can be difficult, but ultrasonography, radionuclide scanning, and fine needle aspiration allow the majority of nodules to be properly characterized. Treatment of differentiated thyroid carcinoma remains controversial. Surgical resection continues to be the most important modality with long survival if the tumor is resected early. Newer imaging techniques have improved the diagnosis of locally recurrent or metastatic disease. Radioactive iodine ablation is indicated for patients with “high-risk” tumors or advanced age. Few patients respond to cytotoxic chemotherapy. In the past decade, advances in the screening and diagnosis of medullary thyroid carcinoma have led to earlier detection with improvement in survival.

Surgical Treatment of Primitive Thyroid Lymphoma

Aims and Background

Primitive thyroid lymphoma, although rare, is becoming more frequent. Its incidence is increasing, from 0.5% in the sixties to 1-5% of all thyroid neoplasms today. The diagnosis of such neoplasms is not always straightforward. In fact, it is often the result of pathologic findings on a gland resected for an apparently benign disease. Surgical dissection may prove more complicated than in standard cases of thyroidectomy for the possible tight adhesions existing between the gland's capsule and the surrounding structures. In cases of capsular infiltration, postoperative external local radiotherapy is indicated.

Methods

A retrospective observational analysis was performed to establish whether patients with incidental thyroid lymphomas who underwent total thyroidectomy for another pathology had major surgical complications and worse prognostic results than patients with an accurate preoperative diagnosis.

Results

Six cases of thyroid lymphoma were retrospectively reviewed: 4 diffuse large B-cell lymphomas and 2 MALT lymphomas. Of these, 2 were correctly preoperatively identified by fine-needle aspiration biopsy and 4 were an unexpected finding at histology: 3 cases of total thyroidectomy carried out for huge hypothyroid goiter in patients affected by Hashimoto's thyroiditis and in 1 case of total thyroidectomy carried out for anaplastic carcinoma in a patient affected by Hashimoto's thyroiditis.

Conclusions

In our experience, a correct preoperative diagnosis was extremely difficult (33%). In patients who underwent fine-needle aspiration, a correct diagnosis was made in 66% of cases. All patients with stage IE lymphoma who underwent total thyroidectomy had equivalent surgical complications and prognosis.

Primary thyroid lymphoma: A case report and review of the literature

Introduction

A rapidly enlarging mass of the anterior compartment of the neck with compressive symptoms may represent, among other diagnosis, a neoplasm of the thyroid gland.

Presentation of case

We describe the case of a 59-year-old woman referred to the endocrine surgical unit because of compressive cervical symptoms for 3 months. The cervical ultrasound revealed a sub-sternal goiter with heterogeneous echo structure and the fine-needle aspirating cytology was inconclusive. Given the large impact of symptoms on life quality, she was submitted to a total thyroidectomy. Histological examination of the surgical specimen revealed the presence of a Diffuse Large B Cell Lymphoma of the thyroid.

Discussion

Primary thyroid lymphomas are rare and there are few randomized studies for diagnostic and therapeutic guidance. New immunohistochemical and molecular techniques have improved the diagnostic accuracy with corebiopsy limiting the role of surgery. The treatment should first include the control of local disease with radiotherapy and/or surgery combined with chemotherapy to control obscure or disseminated disease. Palliative surgery may be needed to relieve airway compression symptoms. Under these circumstances, surgery should be performed by a specialized surgeon to decrease the associated morbidity. The prognosis of patients depends on the histological classification of the tumor and the stage of the disease.

Conclusion

Due to the rarity of the disease, each case must be evaluated and treated individually, since there is not a consensual therapeutic approach.

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Primary thyroid lymphomas are very rare.

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New immunohistochemical and molecular techniques have improved the diagnostic accuracy with corebiopsy limiting surgery.

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Surgery has a small role in PTL and when needed it should be performed by a specialized surgeon to decrease morbidity.

Thyroid Lymphoma: A Single Institution's Experience

BACKGROUND: Primary lymphoma of the thyroid gland is uncommon.

METHODS: The tumor registry at the Penn State Milton S. Hershey Medical Center was searched for all patients carrying a diagnosis of thyroid lymphoma. All available records for these patients were examined and information regarding patient and tumor characteristics, clinical presentation, interventions, and survival were tabulated.

RESULTS: The average age of patient in our series was 67.5 years. There was a 2.7:1 female to male preponderance. Thirteen (60%) patients presented with thyroid nodule(s). Eleven (50%) presented with aerodigestive tract obstructive symptoms. Sixteen (73%) patients had no pre-existing history of thyroid disease; none had known pre-existing Hashimoto's thyroiditis.

CONCLUSIONS: The typical thyroid lymphoma patient is female and elderly with painless thyroid enlargement. Compressive symptoms of the aerodigestive tract are common at presentation and may require urgent intervention. Treatment modalities (XRT, CHOP chemotherapy) and outcomes are distinct from other thyroid malignancies.

EBM RATING: C

Identification of primary thyroid lymphoma with medical imaging: A case report and review of the literature

Primary thyroid lymphoma (PTL) is a rare thyroid malignancy. Clinical diagnosis of PTL may not be easily established based on imaging studies, as the imaging features of PTL are similar to those of lymphocytic thyroiditis and primary thyroid cancer. The present study describes the case of a patient who was confirmed to have PTL by intra-operative pathological diagnosis. On color Doppler ultrasound, the PTL was shown as a significantly enlarged thyroid with reduced gland echoes. Color Doppler flow imaging showed increased blood flow. By computed tomography, the thyroid was revealed to be enlarged with reduced tissue density, particularly in the left lobe and the isthmus. In addition, calcified spots and swollen lymph nodes were evident. The clinical history of the patient was obtained and the imaging results were retrospectively analyzed. The imaging features of PTL were investigated through reviewing the literature. PTL exhibits specific features on medical imaging that aid in distinguishing it from other thyroid diseases. PTL exhibits specific features on medical imaging that aid in distinguishing PTL from other thyroid diseases, which may aid the support for clinical diagnosis and improve the clinical accuracy.

Thyroid ultrasonography

BACKGROUND

The recent prevalence of ultrasonography (US) has facilitated the early detection and qualitative evaluation of thyroid nodules. Furthermore, novel technical developments are extending the application range of US for other thyroid diseases.

METHODS

The use of US to differentiate between thyroid carcinoma and benign nodule, between a metastatic lymph node and a reactive node, between thyroid lymphoma and chronic thyroiditis, and between destruction-induced thyrotoxicosis and Graves' disease is introduced.

RESULTS

Classification systems for thyroid nodule have shown high diagnostic accuracy for thyroid carcinomas except follicular carcinoma. US diagnosis of lymph node metastasis showed high specificity but low sensitivity. Patients who were suspected of thyroid lymphoma based on US findings should undergo incisional biopsy or thyroidectomy for diagnosis of the histologic type if fine-needle aspiration biopsy findings suggest lymphoma. Patients should be carefully followed even if they were diagnosed as negative based on cytologic findings. Measurement of thyroid blood flow is helpful for diagnosing destruction-induced thyrotoxicosis, such as painless thyroiditis, by distinguishing the lesion from Graves' disease.

CONCLUSIONS

Ultrasonography is useful for diagnosing various thyroid diseases, including thyroid carcinoma. The remaining issue to be resolved is the diagnosis of follicular carcinoma. Trials using novel techniques to differentiate these lesions are expected.

Clinical characteristics of primary thyroid lymphoma in Koreans

Primary thyroid lymphoma is a very rare tumor and its prevalence is approximately 0.1% of all thyroid cancers in Korea. Its clinical experience is limited and not familiar to physicians. Therefore, we performed this study to investigate the clinical characteristics of primary thyroid lymphoma in Koreans. We retrospectively analyzed the medical records of the 44 patients with primary thyroid lymphoma from 1991 to 2006 at four major referral hospitals in Korea. Out of 44 patients, eight patients were male and 36 patients were female and their average age was 57 years. Fifty-six percent of patients had underlying Hashimoto's thyroiditis. All but two patients had non-Hodgkin's lymphoma with B cell origin, and eighty percent of patients presented with stage IE or IIE. Twenty-one of 44 patients (48%) had diffuse large B cell lymphoma (DLBCL) and 17 (39%) had MALT lymphoma. Malignancies originating from lymphoid cells were suspected in 10 of eighteen patients with DLBCL (56%) by using fine-needle aspiration cytology (FNAC), and no difference was noted compared with MALT lymphoma (64%). Compared with DLBCL, the patients with MALT lymphoma were more frequently presented with stage I disease (DLBCL vs. MALT lymphoma: 32% vs. 65%, P=0.04). Moreover, in contrast to DLBCL, most of the patients with MALT lymphoma achieved complete response with treatments (DLBCL vs. MALT lymphoma: 53% vs. 94%, P<0.01). Because of the low diagnostic accuracy of FNAC, thyroid biopsy should be considered for the diagnosis of thyroid lymphomas in suspicious cases. The patients with MALT lymphoma were more frequently presented with early stage diseases and this might lead to the favorable outcome to treatments than those with DLBCL.

Clonal relationship between Hashimoto thyroiditis and thyroid lymphoma

BACKGROUND

Although Hashimoto thyroiditis (HT) is a predisposing factor for B-lineage thyroid lymphoma, clonal B-cell populations in HT are rare.

AIM

To investigate whether there is a clonal relationship between HT and primary thyroid lymphoma.

METHODS

Clonalilty and sequence similarity was determined by PCR followed by sequencing and comparing immunoglobulin heavy chain (IgH) gene rearrangement sequences to germline sequences and to each other.

RESULTS

12/20 patients with primary thyroid lymphoma had a previous history and histological diagnosis of HT. Clonal IgH bands associated with a polyclonal background were present in four of these 12 cases of HT; of these four, three had reproducible clonal IgH bands from the subsequently developed lymphoma. The range of similarity (homology) of multiple clonal bands in HT with the germline IgH varied from 90% to 96.3%. Multiple clonal bands in HT had sequence similarity (homology) of 62-100% with the clonal band in the lymphoma from the same patient. At least one clonal band in HT had more than 96% similarity (homology) with the clonal band of lymphoma in all three cases.

CONCLUSION

Sequence similarity between the clonal bands in HT and subsequently developed thyroid lymphoma is supportive of the argument that primary thyroid lymphoma may evolve from HT.

Outcomes of primary thyroid non-Hodgkin’s Lymphoma

Primary non-Hodgkin's lymphoma (NHL) of the thyroid gland is a rare disease with an incidence of 0.5 per 100,000 population. Stages IE and IIE thyroid NHL have been traditionally treated by surgical resection; however, modern treatment consists of chemotherapy and local radiotherapy, and surgery is often reserved for tissue diagnosis and relief of airway compression. We retrospectively reviewed the management and outcomes of nine consecutive patients with thyroid NHL, eight females and one male (median age 63 yr, range 34-71 yr) treated between 1994 and 1999. Five patients had disease stage IE and 4 stage IIE. Median follow-up was 72 mo. Pathohistology and immunohistochemistry identified two patients with mucosa-associated lymphoid tissue (MALT), three follicular center cell lymphoma (FCC), two patients large B-cell lymphoma (BLCL), one a marginal zone lymphoma (MZL), and one patient a peripheral T-cell lymphoma (PTCL). Total thyroidectomy was performed in three patients and subtotal thyroidectomy in four. One (MALT) patient underwent surgery alone; three patients surgery, radiotherapy, and chemotherapy (two FCC, one PTCL); three patients surgery and chemotherapy (one MALT, one FCC, one LBCL); and two chemotherapy alone (one LBCL, one MZL). Median survival was 79 mo (range 13-124 mo). The PTCL patient, a 34-yr-old man, died from disseminated disease at 13 mo despite secondary chemotherapy, and one LBCL patient with extensively invasive local disease died from stroke 17 mo after diagnosis. The remaining seven patients remain in remission with no local or systemic relapse at a mean of 86 mo. With appropriate therapy primary thyroid NHL has a favorable course; however, prognosis depends on the histology, local spread, and the stage of the disease at presentation, as well as the patient's performance status. Surgery in combination with chemotherapy and/or radiotherapy is still warranted for intermediate and high-grade thyroid NHLs, with over 77% of patients achieving long-term remission. Peripheral T-cell lymphoma carries a poor prognosis.

Usefulness of ultrasonography for diagnosis of malignant lymphoma of the thyroid

BACKGROUND

Recent developments in ultrasonography (US) and the prevalence of ultrasound-guided fine needle aspiration biopsy (US-FNAB) has enabled physicians to detect and diagnosis thyroid diseases, including thyroid malignant lymphoma, much more easily.

METHODS

We describe our diagnostic strategy for malignant lymphoma on US screening. We screened possible malignant lymphoma patients by US characteristics such as enhanced posterior echoes.

RESULTS

Among 170 patients suspected of malignant lymphoma between 2000 and 2004, 74 (43.5%) were also diagnosed as having or suspected of lymphoma by US-FNAB. Five patients dropped out, and 67 of 69 patients who underwent surgical examination were pathologically diagnosed as having lymphoma. Finally, 79 (47.9%) of 165 US-suspected patients were confirmed as having lymphoma. Only 21.5% of lymphoma patients complained of rapidly growing goiter.

CONCLUSION

US screening for goiters contributes markedly to diagnosis of lymphoma at an early phase, facilitating early initiation of therapy.

Treatment and survival of patients with thyroid lymphoma: a population-based study with clinical and pathologic reviews

PURPOSE

The purpose of this study was to determine the incidence, clinical and histologic features, and patterns of outcome of thyroid lymphomas.

PATIENTS AND METHODS

A retrospective population-based survey of 38 patients with thyroid lymphoma was taken. Median age was 69 years (range, 33-87 years), with a 1:4 female predominance. Fifty percent of cases had a history of autoimmune thyroiditis, and coexistent thyroiditis was found in 67% of cases in which preexistent thyroid tissue was present. The most common subtype was diffuse large B-cell lymphoma (DLBCL; 63%) followed by extranodal marginal zone lymphoma (ENMZL; 29%). Ten of the patients with DLBCL showed a concomitant low-grade mucosa-associated lymphatic tissue component, and 4 cases of aggressive ENMZL were diagnosed. At diagnosis, 22 patients (58%) had localized disease, and 41% had low-risk international prognostic index scores.

RESULTS

Therapy was diverse and included all possible treatment modalities, none of which showed superiority. A complete clinical response was exhibited in 64% of patients, 14% exhibited a partial response, and 22% developed progressive disease. At a median follow-up of 43 months (range, 0-240 months), 15 patients had relapsed or developed progressive disease. Two-year overall survival rate was 59% for all patients, 68% for patients with localized disease, and 47% for patients with disseminated lymphoma.

CONCLUSION

Many thyroid lymphomas have clinical and histologic features characteristic of ENMZL and belong to this specific clinicopathologic entity.

Fine needle aspiration cytology of primary thyroid lymphoma: a report of ten cases

Primary lymphoma is an uncommon malignancy of the thyroid, comprising of 0.6 to 5 per cent of thyroid cancers in most series. Primary thyroid lymphomas (PTL) occur most commonly in elderly women and are commonly of B- cell origin. These frequently present in clinical stage IE and IIE. We report here ten cases of PTL diagnosed over a period of about 7 years in our institute. Out of these ten cases, nine were diagnosed on fine needle aspiration cytology (FNAC) and one case was misdiagnosed as lymphocytic thyroiditis. This case was diagnosed as Non- Hodgkin's lymphoma on surgical specimen. Five patients are disease free and doing well, while two died of disease and the other two were lost to follow-up. One patient is currently on chemotherapy. The salient clinical, biochemical, radiological features, FNA findings along with diagnostic difficulties are discussed.

Hodgkin's lymphoma of the thyroid: a clinicopathologic study of five cases and review of the literature

Hodgkin's lymphoma rarely involves the thyroid gland. We report the clinical and pathologic features of five cases of Hodgkin's lymphoma that presented as thyroid lesions. All five patients were females, aged 29-59 years. Three patients had a history of chronic thyroiditis and hypothyroidism and two were euthyroid. One patient had a remote history of Hodgkin's lymphoma. Imaging studies showed a 'cold' nodule (three cases) or a diffusely enlarged thyroid gland, resembling goiter or fibrosclerosing thyroiditis (two cases). Thyroid fine-needle aspiration was performed before thyroidectomy in all cases; three of these cases contained some atypical cells, raising the possibility of Hodgkin's lymphoma. Histologically, all cases were classical Hodgkin's lymphoma, nodular sclerosis subtype. The four patients with primary thyroid lymphoma had Stage IIE disease. All patients were treated with surgical excision and chemotherapy, with or without radiation therapy, and were alive after 2 months to 7 years of follow-up. A review of the English literature between 1962 and 2005 revealed 16 cases of thyroid Hodgkin's lymphoma, with a female preponderance and generally favorable outcome similar to the cases in our series. Hodgkin's lymphoma of the thyroid is rare and can mimic a primary thyroid epithelial tumor or thyroiditis clinically. Histologic diagnosis may be difficult due to marked fibrosis. Hodgkin's lymphoma should be considered in the differential diagnosis of thyroid neoplasms.

Management of non-Hodgkin's lymphoma of the thyroid: the Royal Marsden Hospital experience

A retrospective review was conducted of patients treated for thyroid non-Hodgkin's lymphoma (TNHL) at the Royal Marsden Hospital between 1936 and 1996 to determine the effect of radiotherapy (RT) on outcome. 91 patients were identified from the Thyroid Unit Database. There were 77 females and 14 males with a median age of 65 years (range 22-87 years). RT was delivered according to two separate policies: (1) involved field radiotherapy (IFRT) to the thyroid bed and cervical lymph nodes; (2) extended field radiotherapy (EFRT) covering the thyroid bed, cervical and mediastinal lymph nodes. 89 patients received RT as part of definitive treatment following surgery, to a dose of approximately 40 Gy. 25 patients received IFRT and 64 patients EFRT. 27 patients received cytotoxic chemotherapy. 18 patients (72%) treated with IFRT died of TNHL with a median relapse free survival (RFS) of 10 months and a median overall survival (OS) of 21 months. In contrast, only 29 patients (46%) treated with EFRT died of TNHL with a median RFS of 76 months (p = 0.01 for RFS with respect to IFRT and p = 0.04 for OS). Significantly more patients treated with IFRT relapsed locally (52% vs 27%). There was no difference in the rates of systemic relapse (20% vs 22%). EFRT alone for Stage I, but not for Stage II disease, yielded acceptable rates of local control and disease free survival with doses of at least 40 Gy. These historical data strongly support the addition of combination chemotherapy to the treatment regimen in all patients with Stage II disease. Indeed, in recent years this has become the standard of care for all cases of thyroid lymphoma unless the histology is of marginal zone type (mucosa associated lymphoma tissue (MALT) lymphoma).

Detection of monoclonality of the immunoglobulin heavy chain gene in thyroid malignant lymphoma by vectorette polymerase chain reaction

Distinguishing between thyroid malignant lymphoma and lymphocytic thyroiditis (Hashimoto's thyroiditis) is quite difficult and problematic. B cell lymphomas display clonal Ig heavy-chain (IgH) gene rearrangement, and Southern blot hybridization (SBH) is often used for detection of the monoclonality of the IgH gene. However, SBH is often problematic because it requires a large volume of samples. We examined the efficiency in detecting the monoclonality of IgH gene in thyroid malignant lymphomas by vectorette PCR, which we started with only 200 ng of genomic DNA. Monoclonality was detected in 36 of 47 (76.6%) malignant lymphomas, whereas it was not detected in 10 samples of tissue of Hashimoto's thyroiditis. The sensitivity was almost the same as that with SBH in which monoclonality was detected in 33 of 45 (73.3%) malignant lymphomas. These results suggest that vectorette PCR may be a substitute for SBH, and because it requires only a small volume of samples, it may be used in the analysis of aspiration biopsies.

[Non-Hodgkin's lymphoma in the thyroid: case report]

The authors describe the case of a 33 year-old white female, without any clinical or laboratorial evidence of thyroiditis or clinical hypothyroidism, who presented with a rapidly enlarging anterior neck mass. Diagnosis of a follicular non-Hodgkin's lymphoma was made through histopathological and immunohistochemical analysis.

Outcome Analysis for Stage IE and IIE Thyroid Lymphoma

Previous reports have revealed modest results in the management of thyroid lymphoma with radiotherapy alone. This retrospective report evaluates the outcome of patients treated for thyroid lymphoma with radiotherapy alone and with combined modality therapy (chemotherapy and radiotherapy) at a single institution. Twenty-seven patients with stages IE and IIE non-Hodgkin's lymphoma of the thyroid gland were treated between 1960 and 1998 at Barnes-Jewish Hospital, of which 14 patients were stage IE and 13 patients were stage IIE. The median age at diagnosis was 67 years, and there were 21 females and 6 males evaluated. The median follow-up time was 38 months (range: 3-279 months). All patients had histologically proven non-Hodgkin's lymphoma, of which 22 patients (81%) were intermediate grade. Treatment consisted of radiotherapy alone in 19 patients and a combined modality therapy in 8 patients. The median radiation dose to the thyroid bed was 44 Gy, and most patients received a doxorubicin-containing regimen administered prior to radiotherapy. Patient, tumor, and treatment-related characteristics were evaluated using Cox regression analysis. Local-regional tumor control, disease-free survival (DFS), and overall survival (OS) were calculated using the Kaplan-Meier method. Four patients had local relapse in this series, with a crude local tumor control rate of 85%. No factor was determined to be significant for local tumor control. The actuarial 5-year DFS and OS for the entire cohort were 57%, and 56%, respectively. In terms of DFS, both age and stage were statistically significant. The 5-year actuarial DFS for patients less than age 65 years was 83% versus 37% for those more than this age (p = 0.024). Furthermore, the 5-year actuarial DFS for patients with stage I and II disease was 69% and 45%, respectively (p = 0.022). In multivariate analysis, age continued to be significant for DFS (p = 0.049). Overall survival analysis revealed age, local tumor control, and stage to be significant in univariate analysis. Multivariate analysis was further carried out using Cox proportional hazard model, and it revealed age (p = 0.006) and local tumor control (p = 0.007) to be significant. Primary thyroid gland lymphomas have a favorable outcome with appropriate therapy, but prognosis depends on both clinical stage and age at presentation. Because of the risk of both local-regional and distant failure, combined modality approaches that use chemotherapy with radiotherapy are warranted for intermediate- and high grade thyroid lymphoma.

Primary thyroid lymphoma: a retrospective analysis of prognostic factors and treatment outcome for localized intermediate and high grade lymphoma

Non-Hodgkin's lymphoma presenting in the thyroid gland is uncommon. A review of the King Faisal Specialist Hospital and Research Centre (KFSH & RC) experience was performed to assess treatment outcome and prognostic factors in this rare extranodal presentation of localized lymphoma. Sixty patients treated at KFSH & RC between 1975 and 1995 were identified, and their records were reviewed retrospectively. Eight patients who had stage III or IV disease, low grade, or did not complete their prescribed treatment were excluded from the study. There were 38 female and 14 male patients with a median age of 59.5 years at the time of diagnosis (range: 10-87 years). Thirty-five of the 52 patients underwent diagnostic partial or total thyroidectomy at other institutions based on a preoperative assumption of thyroid carcinoma. All 52 patients had non-Hodgkin's lymphoma of intermediate (94%) or high (6%) grade. Detailed staging was carried out in all patients; 16 patients (31%) had disease confined to the thyroid gland (stage IE), whereas 36 (69%) had associated disease in cervical lymph nodes and/or the mediastinum (stage IIE) disease. All patients were treated with curative intent. A total of 18 patients (35%) were treated with a single-modality treatment--radiotherapy alone in 2, chemotherapy alone in 13, and surgery alone in the remaining 3 patients. The majority of patients (34/52; 65%) were treated with a combined-modality approach. The overall relapse-free survival (RFS) and overall survival (OS) at 5 years were 72% and 88%, respectively. There were no significant differences in outcome between those treated with single-modality and those with combined-modality therapy. A univariate analysis showed that the presence of mediastinal lymph node involvement was the most important prognostic factor affecting both RFS and OS. Patients with Hashimoto thyroiditis and without "B" symptoms were found to have a significantly higher RFS without influence on the OS. However, patients who had a good performance status (PS) of 0, 1, and 2 were found to have a significantly higher overall survival in comparison to those with poor performance status. Age, sex, stage, histology, lactic acid dehydrogenase level, tumor bulk, and the treatment modality were not found to correlate with RFS or OS. Mediastinal involvement and PS were found to be the most important independent prognostic factors influencing RFS and OS.

Malignant lymphoma of the thyroid gland: a clinicopathologic study of 108 cases

We report a retrospective clinicopathologic study of 108 primary thyroid gland lymphomas (PTLs), classified using the REAL and proposed WHO classification schemes. The patients included 79 women and 29 men, with an average age of 64.3 years. All patients presented with a thyroid mass. The PTLs were classified as marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) or MZBL (n = 30), diffuse large B-cell lymphoma (DLBCL) with MZBL (n = 36), DLBCL without MZBL (n = 41), and follicle center lymphoma (FCL; n = 1). Excluding the FCL, features of lymphomas of MALT-type were identified in all groups, despite a follicular architecture in 23% of cases. Lymphocytic thyroiditis (LT) was identified in 94%. Ninety-one percent of patients presented with stage IE or IIE disease, whereas 69% had perithyroidal soft tissue infiltration. All patients were treated with surgical excision followed by adjuvant therapy (76%): chemotherapy (15%), radiation (19%), or a combination of radiation and chemotherapy (42%). Disease-specific survival was 82% at last follow up (mean, 82.8 mos) and 79% at 5 years. Statistically, stages greater than IE, presence of DLBCL, rapid clinical growth, abundant apoptosis, presence of vascular invasion, high mitotic rate, and infiltration of the perithyroidal soft tissue were significantly associated with death with disease. No patients with MZBL or stage IE disease died with disease. In summary, PTLs typically occur in middle- to older-aged individuals as a thyroid mass, with a predilection for females. Despite their histologic heterogeneity and frequent simulation of other lymphoma subtypes, virtually all PTLs are lymphomas of MALT-type arising in the setting of LT. Mixed DLBCL and MZBL are common. Overall, PTLs have a favorable outcome with appropriate therapy, but prognosis depends on both clinical stage and histology. MZBL and stage IE tumors have an excellent prognosis, whereas tumors with a large cell component or DLBCL or stage greater than IE have the greatest potential for a poor outcome.

Diagnosis of thyroid malignant lymphoma by reverse transcription-polymerase chain reaction detecting the monoclonality of immunoglobulin heavy chain messenger ribonucleic acid

Distinguishing between thyroid malignant lymphoma and lymphocytic thyroiditis (Hashimoto's thyroiditis) is quite difficult and problematic. Molecular techniques to detect clonal lymphoid proliferation based on Ig heavy chain (IgH) gene rearrangement may be used to facilitate more accurate diagnosis of malignant lymphoma. We recently established a method for diagnosing thyroid tumors by analyzing ribonucleic acids (RNAs) extracted from the needles used for fine needle aspiration biopsy (aspiration biopsy-RT-PCR). By applying the aspiration biopsy-RT-PCR method to detection of the monoclonality of IgH messenger RNA (mRNA), an accurate molecular-based diagnosis of malignant lymphoma can be established as an adjunct to cytological diagnosis. We first studied RNAs from fresh tissues samples of 8 cases of Hashimoto's thyroiditis and 18 malignant lymphomas to detect the monoclonality of IgH mRNA by seminested RT-PCR. Monoclonality was detected in 8 of 18 (44.4%) malignant lymphomas, but in none of the 8 cases of Hashimoto's thyroiditis. We then studied aspirates from 10 cases of thyroid malignant lymphoma, 4 cases of Hashimoto's thyroiditis, and 1 case each of adenomatous goiter and papillary carcinoma. Monoclonality was detected in the aspirates from 4 of 10 malignant lymphomas (40%), but not from other tissues. Thus, RT-PCR detection of monoclonality of IgH mRNA in addition to cytological examination may be useful in diagnosing thyroid malignant lymphoma.

Primary T-cell lymphoma of the thyroid

BACKGROUND

The routine use of immunocytochemical analysis has led to the recognition that many thyroid neoplasms previously diagnosed as anaplastic or small cell carcinomas are actually lymphomas of the thyroid. The great majority are B-cell lymphomas which can be associated with Hashimoto's thyroiditis. In spite of this, thyroid lymphomas are still not commonly recognized as a significant part of thyroid differential diagnosis.

METHODS

A rare case of a primary T-cell lymphoma of the thyroid gland is presented along with general clinical history and physical findings which should make the practitioner suspicious of a thyroid lymphoma. The usefulness of radiology scans and fine-needle aspiration are discussed.

RESULTS

Both prognosis and treatment options are very different for thyroid lymphomas and anaplastic carcinoma.

CONCLUSIONS

Cyclophosphamide/adriamycin/vincristine/prednisolone chemotherapy/radiotherapy regimens have proven to be very effective for most thyroid lymphomas.

Radiotherapy planning techniques for thyroid cancer

External beam radiotherapy has a role in each histological type of thyroid cancer. For treatment confined to the thyroid bed, an antero--oblique wedged pair of beams is simple to apply. More frequently, however, the volume needs to include both sides of the neck and adequate dose must be given down to the level of the suprasternal notch, precluding use of lateral fields. Thus, anterior and posterior fields are usually necessary, extending from the tips of the mastoid processes or hyoid down to the carina and laterally to include both sides of the neck and supraclavicular fossae. The mandible and infraclavicular portions of both lungs are shielded, but there is no midline lead in the phase one volume. A mid-plane dose of 46 Gy given in 23 daily fractions results in an acceptable early radiation reaction and will avoid late damage to the spinal cord. Because of considerable variation of interplanar distance along the length of the volume, a lateral simulator film should be taken to determine the maximum cord dose. For most patients, a three-dimensional CT planned phase two volume will be required and should be determined prior to completing phase one. The optimum beam arrangement, usually incorporating conformal beam shaping assisted by use of a multileaf collimator, should avoid further dose to the cord. If there is additional dose to the spinal cord, this phase can be introduced before 46 Gy is reached.

External radiation therapy in the treatment of thyroid malignancy

The use of external beam radiation therapy in the management of thyroid malignancy is reviewed. Information from retrospective studies is presented and critically appraised as to the situations in which radiotherapy may be of benefit when used as part of initial treatment in the various thyroid malignancies. in particular, the role of external beam radiation and adjuvant treatment in addition to iodine-131 in differentiated thyroid cancer in medullary thyroid cancer are discussed.

Unusual types of thyroid neoplasms

This article discusses several unusual forms of primary thyroid neoplasms. The TCV of PTC and insular thyroid carcinoma appears to have a more aggressive clinical behavior than DTC in most patient groups and may respond to thyroid hormone suppression and radioiodine. Anaplastic thyroid carcinoma, which may develop from differentiated thyroid tumors, has a poor prognosis which may be altered by surgery and radiation therapy but not typically by radioiodine and thyroid hormone suppression. Primary squamous cell carcinoma of the thyroid is an unusual entity that may be associated with a clinical syndrome that includes leukocytosis, fever, and hypercalcemia. Primary thyroid lymphoma is frequently associated with Hashimoto's thyroiditis and should be considered especially in older patients with rapidly enlarging thyroid masses. Although there are no studies assessing this issue, it seems reasonable that patients who have undergone thyroidectomy for neoplasms of thyroid cells that are poorly differentiated and do not concentrate radioiodine (e.g., squamous cell, anaplastic) should receive sufficient thyroid hormone suppression, if tolerated, to reduce TSH (third-generation assay) to approximately 0.1 to 0.3 mu U/mL, because TSH may be a growth factor. If, however, the tumor concentrates or responds to radioiodine, suggesting more differentiated cells (e.g., TCV, insular carcinoma), the target TSH level (third-generation assay) should range from 0.01 to 0.1 mu U/mL, as tolerated. Patients with primary thyroid neoplasms arising from cells other than thyrocytes (e.g., lymphoma) can be maintained at a TSH level of 0.5 to 1.5 mu U/mL. Our conclusions and analyses are often based upon small, retrospective, poorly controlled reports, and further studies are required to allow a better understanding of the evaluation and treatment of these neoplasms.

Non-Hodgkin's lymphoma of the thyroid. A clinical study of twenty-two cases

Non-Hodgkin's lymphoma (NHL) of the thyroid gland is a rare disease. In the present study, the survival rate and characteristics were retrospectively analyzed in 22 patients with stage IE and IIE thyroid NHL treated with radiotherapy with or without combination chemotherapy. Seventeen NHL had histological evidence of lymphoma of mucosa-associated lymphoid tissue (MALT) type. The 5-year survival rate was 85% in all patients, with 100% and 63% respectively, for stage IE and stage IIE patients. The highly significant factor correlated with decreased determinate survival was concomitant stridor.

Non-Hodgkin's lymphoma of the thyroid: a retrospective review of all patients diagnosed in Nottinghamshire from 1973 to 1992

The pathological and clinical features were reviewed of all primary non-Hodgkin's lymphomas (NHL) of the thyroid gland diagnosed between 1973 and 1992 in the population (1.1 million) served by the Nottingham and North Nottinghamshire Health Authorities. Of the 43 patients with histologically proven NHL, three had low grade mucosa associated lymphoid tissue (MALT) lymphomas (Stage IEA, 2; Stage IIEA, 1), 35 had intermediate or high grade lymphomas, Stage IEA or IIEA (intermediate MALT, 2; high grade MALT, 14; B-cell diffuse centroblastic, 17; anaplastic large cell (Ki-1) of null cell type, 1; high grade unclassifiable, 1), and one had unclassifiable NHL Stage IIEA. One patient had Stage IIIEA disease (high grade MALT) and three had stage IVA disease (high grade MALT, 2; B-cell diffuse centroblastic, 1). The median age was 68 years (range 45-86) with a female: male ratio of 6:1. For the 35 patients with intermediate or high grade thyroid NHL (Stages IEA and IIEA) the 5- and 10-year cause specific survival was 60%. The 21 patients treated between 1985 and 1992 initially with chemotherapy (except stage IEA (< 5 cm diameter) had a 5-year cause specific survival of 69% (95% CI 48-90) compared with 46% (95% CI 19-73) for the 14 patients treated between 1973 and 1984 with initial radiotherapy (Chi 2 = 1.62). The survival of those patients with intermediate or high grade MALT lymphomas was not significantly greater than of those patients with B-cell diffuse centroblastic NHL.

Non-Hodgkin's lymphomas (NHL)

This synthesis of the literature on radiotherapy for non-Hodgkin's lymphomas is based on 158 scientific articles, including 16 randomized studies, 18 prospective studies, and 90 retrospective studies. These studies involve 14,137 patients. Non-Hodgkin's lymphomas are highly radiosensitive, and local recurrence following radiotherapy is unusual. Radiotherapy probably cures approximately 50% of both low-grade and high-grade malignant NHL at stage I. Involved field is apparently sufficient, however, higher doses are required for high-grade malignant lymphomas. Chemotherapy is recommended for stage II. Consolidation radiotherapy after chemotherapy may increase the number of complete remissions. The value of adjuvant radiotherapy has not been confirmed. Radiotherapy plays a limited role at stages III and IV. Radiotherapy is clearly indicated for extranodal localized disease in the skin and in the orbit of the eye. It is important to identify groups and subgroups in whom radiotherapy alone is sufficient, ie, the risk for distant recurrence is small. MALT lymphoma belongs to this group. Radiotherapy is often valuable in palliative situations.

Lethal tracheal dissolution during treatment for thyroid lymphoma

Background - A case of primary thyroid T cell lymphoma leading to lethal tracheal perforation during chemotherapy is described.

Primary non-Hodgkin's lymphoma of the thyroid with bone marrow infiltration at presentation

Primary non-Hodgkin's lymphoma of the thyroid is predominantly a disorder of elderly females. Most patients present with limited disease and receive local irradiation. Presentation with advanced disease is uncommon and, consequently, bone marrow examination is not always done. We report a patient with primary thyroid lymphoma who had bone marrow infiltration at presentation and discuss the importance of this investigation in management.

The significance of MALT histology in thyroid lymphoma: a review of patients from the BNLI and Royal Marsden Hospital

Data from a series of 45 patients with Stage I and II non-Hodgkin's lymphoma (NHL) of the thyroid gland were analysed retrospectively to determine the incidence and prognostic significance of histopathological features of tumour origin from mucosa associated lymphoid tissue (MALT). The overall 5- and 10-year cause specific survival from NHL for the series was 79%. Evidence of tumour origin from MALT was the only significant prognostic factor for overall survival identified by multivariate analysis of the series (P < 0.01). A total of 31 (69%) tumours showed such evidence, the cause specific patient survival from NHL at 5 and 10 years being 90% compared with only 55% at 5 years for the 14 patients without such evidence. For patients given initial treatment with radiotherapy alone, those with evidence of tumour origin from MALT had a relatively low relapse rate and a relatively high success rate from salvage therapy, compared with a relatively high relapse rate and negligible success from salvage therapy in those without evidence of such tumour origin.

Thyroid lymphoma. The case for combined modality therapy

BACKGROUND

Radiation therapy with or without surgery is generally considered standard treatment for lymphoma of the thyroid. Because of the small number of cases, the role of chemotherapy or combined modality treatment is difficult to determine.

METHODS

The published literature was analyzed, supplemented by a series from Yale, for the incidence of local and distant relapse after radiation therapy, chemotherapy, or combined modality treatment for Stage I-II thyroid lymphoma. Patients with advanced disease or in whom radiation was probably inadequate were excluded. Only patients receiving an anthracyline-based regimen were considered in the group with chemotherapy. Patients receiving single agents or non-anthracycline-based regimens were excluded from analysis or, if they also received radiation, were included in the group that received radiation only.

RESULTS

Including a series from Yale, a total of 211 patients with Stage IE and IIE thyroid lymphoma were identified. Distant and overall relapse rate were significantly lower in the group that received combined modality treatment. Local relapse was also less, but the difference was not statistically significant. In a small number of patients with disease confined to the neck, the results with radiation were similar to combined modality treatment if the mediastinum was included in the treatment port.

CONCLUSION

Although mucosa-associated lymphoma tissue lymphomas are thought to have a low distant recurrence rate and are therefore often treated with local therapy alone, a review of the published literature suggests that 30% of thyroid lymphomas with clinically localized disease will have a distant relapse. The addition of chemotherapy to radiation significantly lowered distant and overall recurrence.

Non-Hodgkin's lymphoma of the thyroid gland: prognostic factors and treatment outcome. The Princess Margaret Hospital Lymphoma Group

PURPOSE

Non-Hodgkin's lymphoma presenting in the thyroid gland is uncommon. A review of the Princess Margaret Hospital experience was performed to assess treatment outcome and prognostic factors in this rare extranodal presentation of localized lymphoma.

METHODS AND MATERIALS

Fifty-two patients treated at the PMH between 1978 and 1986 were identified and their records reviewed retrospectively. Staging procedures revealed 16 patients with Stage I, 28 with Stage II, and eight with Stages III or IV disease. Five patients were treated on a protocol designed for anaplastic carcinoma of thyroid and they were excluded from detailed analysis. Of 39 patients with Stages I and II disease, 18 were treated with radiotherapy alone, three chemotherapy alone, and 18 combined modality therapy. Combined modality therapy was used mainly in patients with large tumor bulk.

RESULTS

The overall 5-year actuarial survival and cause-specific survival were 56% and 64%, respectively. The overall relapse-free rate was 61% at 5 years. Among the 39 patients with Stages I and II disease, the 5-year actuarial survival, cause-specific survival, and relapse-free rate were 64%, 73%, and 66%, respectively. There were no significant differences in outcome between those treated with radiotherapy alone and those treated with combined modality therapy (cause-specific survival: p = 0.25, relapse: p = 0.06). A univariate analysis showed that the only variable to reach statistical significance was tumor bulk. Age was marginally significant while stage and histology were not statistically significant, possibly due to the fairly homogeneous distribution of patients in each of these variables. Patients with progression or relapse of lymphoma after initial treatment frequently died of disease. Isolated gastrointestinal relapses occurred in three cases, representing 27% of all relapses.

CONCLUSION

Based on the above results, we recognize that the majority of patients with localized thyroid lymphoma require combined modality therapy and we recommend radiotherapy alone only for a small, select group of patients with Stage I disease and small tumor bulk.

Clinical aspects of primary thyroid lymphoma: diagnosis and treatment based on our experience of 119 cases

We describe the clinical aspects of primary thyroid lymphoma, particularly diagnostic procedures and successful therapy based on our observation of 119 patients with primary thyroid lymphoma. Thyroid lymphoma occurred exclusively in the thyroid gland of patients with Hashimoto's thyroiditis as a rapidly growing mass in the thyroid gland. Therefore, progressively enlarging goiter and compression symptoms were the most common clinical manifestations. A significant number of patients in our series had subclinical hypothyroidism (14%) or overt hypothyroidism (27%) because of the coexistence of Hashimoto's thyroiditis. Whenever thyroid lymphoma is suspected, we recommend an ultrasound scan of the thyroid gland and fine needle aspiration biopsy as initial diagnostic procedures. Thyroid ultrasound showed characteristic asymmetrical pseudocystic pattern in 43 of the 46 patients (93%), and thyroid cytologic examination showed abundant monomorphic infiltration of lymphoid cells. Among 83 patients who underwent fine needle aspiration biopsy, 65 patients (78.3%) were diagnosed correctly and 10 patients (12%) had borderline cytologic results. Thus, 90% of patients with thyroid lymphoma were diagnosed or the diagnosis suspected based on fine needle aspiration biopsy. To confirm the diagnosis of lymphoma histologically and to determine the degree of malignancy, open biopsy taking 2-3 g tissue should be done for all cases. Treatment of thyroid lymphoma does not require resection of all lymphoma tissue or total thyroidectomy. Our successful treatment is radiation therapy combined with six courses of CHOP chemotherapy (cyclophosphamide, adriamycin, vincristine, prednisolone). This mode of therapy improved the 8-year survival rate to nearly 100% regardless of the histological type of malignancy.

Primary malignant lymphoma of the thyroid: a clinicopathological analysis

A retrospective analysis of 70 patients with primary malignant lymphoma of the thyroid treated at this institute between 1965-1983 has been conducted. The clinicopathological features and prognostic factors have been studied. The mean age was 67.5 years and there was a marked female:male ratio of 8:1. A total of 32 (45.7%) Stage IE and 38 (54.3%) Stage IIE patients were identified. In 64 cases histological material was reviewed and classified employing the Kiel classification. All the tumors were of B cell lineage and the majority were follicle center cell type. A biopsy only was performed in 27 patients, lobectomy in 11 patients, subtotal thyroidectomy in 27 and macroscopic thyroidectomy in 5 patients. All patients were treated with radiotherapy. The overall 5-year survival was 42%, with 63% for Stage IE and 27% for Stage IIE. The corrected overall 5-year survival was 49% with 68% for Stage IE and 36% for Stage IIE. The corresponding overall relapse free survival was 42% with 60% for Stage IE, and 31% for Stage IIE. Factors of prognostic significance for relapse and survival were stage, radiotherapy dose, stridor, retrosternal extension and fixation.

A radiotherapeutic experience for localized extranodal non-Hodgkin's lymphoma: prognostic factors and re-evaluation of treatment modality

Between 1966 and 1988, 149 patients were treated with radiotherapy for localized extranodal lymphoma. The average total dose given was 39.8 Gy for low grade disease and 48.7 Gy for all other disease. Of the 149 patients, 60 also received adjuvant chemotherapy. Twenty-four had low grade lymphoma, 109 had intermediate grade disease, and 16 had high grade disease, histologically. The distribution of histological grade and T/B phenotype varied with the primary site. Low grade lymphomas were found mainly in the orbit, and T-cell lymphomas were found in the nasal cavity and nasopharynx. The 5-year survival rates according to tumor location were 89% for oral cavity, 86% for paranasal sinus, 83% for thyroid, 69% for orbit, 47% for Waldeyer's ring (WAR), 44% for testis, 23% for CNS, 21% for nasal cavity and 60% for other sites. Histological grade and T/B phenotype both had prognostic importance. Combined chemotherapy significantly improved the survival rate only for disease with intermediate or high grade histology. Other prognostic factors according to the primary site were the bulk of lymph node for WAR disease, the radiation dose for CNS disease, bone erosion for orbital disease, stridor for disease of the thyroid, and the tumor stage for disease of both the testis and the thyroid.

Thyroid cancer: a computer-assisted review of 5287 cases

Retrospective computer analysis of all reportable cases of thyroid cancer for the Rocky Mountain Cancer Data Systems between 1973 and 1983 was undertaken. Follow-up data were available for periods of 5 to 10 years. All major histologic findings are reviewed with regard to distribution, prognostic factors, mortality rates, and some treatment modalities. Interesting observations determined by this study include: (1) the significantly greater mortality rates seen in patients with thyroid cancer after 50 years; (2) the lack of increased mortality rates in young patients with differentiated cancer; (3) the poorer prognosis of male patients of equivalent age to female patients in all histologic types of cancer in the first 5 years; (4) the lack of sexual difference in influencing mortality rates after the first 5 years in differentiated cancers and lack of sex as a prognostic indicator in undifferentiated cancers; (5) the excellent prognosis of patients with localized differentiated and medullary cancers and a better-than-expected prognosis in the undifferentiated group; (6) the clear need for combined therapy (surgery and irradiation) in regional medullary cancer; (7) the observation that localized thyroid lymphoma had a higher mortality rate than had regional thyroid lymphoma; and (8) a significantly higher mortality rate in patients older than 79 years with differentiated cancer.

Primary thyroid lymphoma in childhood: treatment with chemotherapy alone

A 7-year-old boy developed primary non-Hodgkin's lymphoma (NHL) localized to the thyroid gland and was treated with combination chemotherapy alone. He has been continuously disease-free for 5 years since diagnosis, and is probably cured, without evidence of hypothyroidism or other unwanted late sequelae of external beam irradiation. Chemotherapy, alone, should be considered for the treatment of most, if not all, cases of localized NHL in childhood.

Thyroid lymphoma

We have reviewed the local experience of 15 cases of thyroid lymphoma with a view to documenting the epidemiology, presentation, management and prognostic factors governing outcome for this rare condition. All the patients were European despite the fact that 15 per cent of the local population is either Maori or Polynesian. The average age at presentation was 62 years and 13 of the 15 patients were women. The duration of symptoms was short: on average 9 months. Where feasible a definitive resection of the lesion was performed but this could only be performed in six of the 15 cases. The commonest histological type was non-Hodgkin's lymphoma which accounted for 14 of the 15 cases with the large cell variant being the most common (five cases). The mean period of follow-up was 3.3 years: only eight patients were alive and well at that time. The prognostic factors that influenced outcome were: (1) the histology of the lesion - large cell lymphoma carried a bad outlook; (2) whether the lesion could be totally resected or not - five out of six patients undergoing total resection remain alive and well; (3) the presence of pre-existing Hashimoto's thyroiditis was a favourable prognostic factor as only one patient without underlying Hashimoto's disease or positive antithyroid antibodies was alive at the end of the study; (4) male sex may also be an unfavourable prognostic factor as both men in the study died of disease 0.3 and 5 years after diagnosis.