Thymoma: a clinical and pathological study of 65 cases

The role of preoperative radiotherapy for invasive thymoma

Six patients with large invasive thymomas were treated by preoperative irradiation with 12 to 20 Gy before total or partial resection of the tumor. The responses of these 6 thymomas were estimated on the chest radiograms as follows; complete response in 2 patients, partial response in 3 and no response in one. Although the clinical responses varied, the surgical specimens of all the tumors pronounced severe fibrosis, probably not related to irradiation, and necrotic foci with a few viable tumor cells. Total resection of the thymoma was performed in 3 patients and subtotal resection in 3. Adhered or involved surrounding tissues such as the pericardium, pleura and/or veins were also resected in most patients. Preoperative radiotherapy facilitated total or subtotal resection of the invasive thymoma mass by reducing the tumor volume.

Initial chemotherapy followed by surgery in malignant thymoma

Initial combination chemotherapy with cisplatinum, adriamycin and cyclophosphamide was given prior to surgery in a young woman with an unresectable malignant thymoma. Complete remission was achieved following three cycles of chemotherapy. Subsequent thymectomy revealed no evidence of residual malignancy. Prolonged remissions following cisplatin-based chemotherapy have recently been achieved in metastatic thymoma. Initial chemotherapy should now be considered prior to surgery or radiotherapy in those patients presenting with very bulky or unresectable disease.

DNA flow cytometry of thymomas

Forty-seven thymomas have been examined by DNA flow cytometry and results correlated with histology, stage, associated clinical features and survival. Twenty-five cases were DNA diploid, 14 were aneuploid and no results could be obtained for eight cases. The presence of aneuploidy correlated with more advanced (stage II and III) disease and the presence of myasthenia gravis and was more frequent in epithelial predominant thymomas. Tumour recurrence was more frequent in DNA aneuploid tumours, stage II/III disease and epithelial predominant neoplasms. Multifactorial analysis showed that DNA aneuploidy was predictive of tumour recurrence independent of the effects of stage and histology.

Correlations between histological type, clinical behaviour, and prognosis in thymoma

Seventy four cases of thymoma were reclassified into three histological categories--cortical (30), medullary (9), and mixed (34) (the remaining patient had an intrathymic thymoma)--for an investigation of the relation between histological type, clinical behaviour, and long term prognosis. There were significant differences between the histological types in the frequency of myasthenia gravis and of the different tumour stages, the mean age of the patients, and prognosis. Myasthenia gravis occurred more commonly in patients with cortical (33%) and mixed thymoma (35%) than in patients with medullary thymoma (11%). Five, 10, 15, and 20 year actuarial survival was 100% for medullary thymoma; 85%, 76%, 65% and 65% respectively for mixed thymoma; and 52%, 45%, 45%, and 45% for cortical thymoma. Medullary thymoma is a benign tumour arising late in life and there was no mortality in this series after surgery alone. Cortical thymoma usually presented in middle age and must be regarded as malignant; mortality was 50% at five years despite a multidisciplinary approach, with surgery and postoperative radiotherapy in all patients and chemotherapy in selected cases. Mixed thymoma had a better prognosis than cortical thymoma, but must be regarded as potentially malignant. One third of the total patients had died by 10 years despite radical tumour resection.

Chemotherapy of invasive thymoma. A retrospective study of 22 cases

The authors report on combination chemotherapy in 22 patients (seven men, 15 women; age 20-67, median 38.5 years) with incompletely resected invasive thymoma. Twelve of 22 patients have had prior radiotherapy of the tumor (four of 12 local failure, eight of 12 remote metastases). By subsequent chemotherapy five of 12 obtained complete remission (CR). One of them died by relapsed tumor, another by an intercurrent infection. At 5 years after diagnosis the survival rate of the 12/22 patients was 33% (Kaplan-Meier). Ten of 22 patients received chemotherapy as primary treatment of incompletely resected thymoma. Four of 10 obtained CR. One of them was lost during follow-up, the others received adjuvant irradiation of the mediastinum and are free of disease. Two of ten obtained partial remission (PR), but relapsed within 6 months after chemotherapy. At 3 years after diagnosis the survival rate of the 10/22 patients was 34%. Thirteen of 22 patients received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or CHOP/bleomycin as first chemotherapeutic regimen. Five of them achieved CR. Cyclophosphamide, vincristine, and prednisone (COP) or COP plus procarbazine (COPP) was administered to six of 22. Three of them obtained a CR and one a PR. In an alternating manner COPP and Einhorn regimens were given to two of 22, one of which had a CR. In one of 22 the doxorubicin, bleomycin, cisplatin, prednisone (BAPP) regimen was followed by a PR. The authors conclude that combination chemotherapy is effective in the first-line postsurgical treatment of incompletely resected thymoma and also in the treatment of local or metastatic relapses after radiotherapy.

Macrophages and interdigitating reticulum cells in normal thymus and in thymoma: an immunohistochemical study

The distribution and immunophenotype of macrophages and interdigitating reticulum cells were investigated on frozen sections of seven normal thymuses and 10 thymomas. In normal thymus, macrophages were mainly located in the cortex, were markedly PAM-1+/MAC+, weakly Leu-M3+ (CD14), T4+ (CD4), T9+ and OKM-1+ (CD11b). Interdigitating reticulum cells were mainly located in the medulla and were pan-Leu+ (CD45), T4+(CD4+), HLA-DR+; furthermore, they were also often TAC+ (CD25) and T9+. Thymomas were composed of cytokeratin-containing epithelial cells admixed with variable proportions of T6+ (CD1a) lymphocytes. As defined by the histological features two thymomas were lymphocyte-rich, five were mixed type and three were epithelial-rich; eight thymomas were mainly composed of cortical epithelial cells and two were composed of spindle epithelial cells suggesting a medullary origin. In all cases, thymoma-associated macrophages were markedly PAM-1+/MAC+; they were numerous, and regularly distributed throughout the tumour. The density of macrophages per unit area was similar to that of the normal thymus, and was not influenced by the histological type or by the lymphocyte content of the tumour. Interdigitating reticulum cells were few and were confined to the areas of medullary differentiation.

Thymoma and pancytopenia

A case of thymoma associated with aplastic anemia is presented. Various therapeutic modalities have been tried and a complete remission finally obtained by antithymocyte globulin.

Evaluation of the malignant grade of thymoma by morphometric analysis

To determine the histologic grade of malignancy of thymoma, the nuclear areas of epithelial cells of 42 thymomas, 14 thymic hyperplasias, and ten normal thymuses were measured by morphometry and the results were compared with the extent of disease, association with myasthenia gravis (MG), and histologic subtypes of the thymomas. The nuclei of epithelial cells of thymomas were significantly larger than those of both of thymic hyperplasias and normal thymuses (P less than 0.01). The nuclei of epithelial cells of invasive thymomas were significantly larger than those of noninvasive ones (P less than 0.001). In the noninvasive group, the nuclei of epithelial cells of thymomas associated with MG were significantly larger than those without MG (P less than 0.02), and were similar to those of invasive thymomas. These results confirm that invasive thymomas are morphometrically malignant tumors, and suggest that noninvasive thymomas associated with MG might have malignant potential.

Immunoglobulin and T-cell receptor genes in thymomas: genotypic evidence supporting the nonneoplastic nature of the lymphocytic component

On the basis of morphologic and immunophenotypic studies, it is generally accepted that the lymphocyte population in thymomas is not neoplastic. We studied 10 thymomas with restriction endonuclease and Southern blot/DNA hybridization methods in an attempt to provide genotypic evidence in support of this hypothesis. The clinical, gross, and microscopic features of each case were reviewed and found to be entirely consistent with the diagnosis of thymoma. In addition to conventional histologic methods, we also studied each tumor by immunohistologic techniques. The lymphocytes generally had an immunotype characteristic of immature cortical thymocytes, and the epithelial cells were uniformly stained by antikeratin antibodies. DNA probes for the T-cell receptor beta-chain gene and immunoglobulin genes (C kappa, C lambda, and JH) were used in the genotypic studies. No gene rearrangements were detected in any of the thymomas. This study provides additional evidence that clonal proliferations of T or B lymphocytes are not present in thymomas; therefore, these cells are almost certainly not neoplastic. The results also provide a basis for the effective use of restriction endonuclease and Southern blot/DNA hybridization analysis in the differential diagnosis of non-Hodgkin's lymphoma and thymoma.

Thymoma. A clinicopathologic review

The clinical and pathologic features of 283 patients with thymoma treated at the Mayo Clinic (147 female and 136 male; ages 16 years to 90 years; mean, 52 years) were examined. Forty-six percent of the patients had myasthenia gravis and 10% had other paraneoplastic phenomena. The tumors were locally invasive at operation in 32%, including 6% with metastasis to lung or pleura. Intrathoracic recurrence was noted postoperatively in 15% of those who had total excision and distant metastasis developed in 3% of patients. Thirteen percent died of their thymomas and 16% died of myasthenia. Overall 5-year survival was 67% and 10-year survival was 53%. Poor prognostic factors included presence of tumor-related symptoms, large tumor size, local invasion or metastasis in initial operation, and predominantly epithelial histologic features. Although true thymomas are composed of cytologically benign elements, they show a propensity for local invasion and intrathoracic recurrence. They rarely metastasize outside the thorax.

Malignant thymoma associated with progressive systemic sclerosis

A 65-year-old man manifested certain features of scleroderma several years before discovery of malignant thymoma. Following tumor resection, the signs and symptoms of scleroderma did not improve, and the patient experienced the abrupt onset of renal failure with malignant hypertension 7 months after the operation. The scleroderma renal crisis caused terminal renal failure, which was treated by chronic hemodialysis. This is the second reported case of thymoma associated with progressive systemic sclerosis (PSS). The authors suggest that thymoma and various immunologic disorders have a common etiologic factor which has not yet been found. This case emphasizes that thymectomy frequently has little effect on the course of the immunologic disease. The implications of the association of thymoma and PSS are discussed.

Thymoma presenting as a superior vena cava syndrome remission following therapy

A 45-year-old male developed myasthenia gravis 8 years ago. He received prednisone for 3 years, and resumed complete clinical remission. Five years later, he was admitted with obstruction of the superior vena cava. Invasive thymoma was diagnosed by chest X-ray and an open lung biopsy. Radiation followed by combination chemotherapy with cyclophosphamide, vincristine, and prednisone induced a complete remission. The patient remained disease-free for more than 20 months after the first admission to our department. To the best of our knowledge, superior vena cava syndrome as the presenting symptom of thymoma has never been reported previously.

Diagnosis of thymoma by fine-needle aspiration cytology: light and electron microscopic study of a case

A case of thymoma was diagnosed by fine-needle aspiration cytology based on an intimate admixture of a biphasic cell population consisting of epithelial cells and lymphocytes from an intrathoracic mass. The diagnosis was later confirmed by light and electron microscopic examination of the tissue.

A proposal for treatment of invasive thymoma

Eleven patients with invasive thymoma were treated with radiotherapy. All patients had gross anterior mediastinal tumors that invaded the adjacent structures, four of whom showed intrathoracic dissemination. Before radiotherapy, only one had macroscopic complete resection of the tumor, and another had partial resection; the other nine patients underwent biopsy only. All 11 patients achieved complete remission after radiotherapy, eight of whom have been free from relapse for 31 to 202 months. Three patients experienced recurrence within the thorax but outside the radiation fields. Even after whole mediastinal irradiation, recurrence could occur in the pleural cavity. Therefore, extended radiation fields including the entire hemithorax is recommended. Intensive combination chemotherapy was administered for two patients with recurrence and they achieved complete remission. A possible role of intensive chemotherapy in induction phase for invasive thymomas is discussed.

Primary malignant thymoma in a 6-year-old boy

Although not uncommon in adults, thymomas are the least common mediastinal tumors in children. The behavior of these tumors in children is partially distinct with a much more rapid course and a poor prognosis. A symptom-free 6-year-old boy was treated for malignant thymoma detected incidentally on a chest X-ray in a school mass examination. At operation, the tumor was found to have already invaded the surrounding tissue. Complete removal at the base of the invasive tumor is the treatment of choice.

Primary anterior mediastinal tumors in children and adults

This review details pertinent anatomical, radiological, pathological, and clinical information regarding primary anterior mediastinal tumors. Although the majority of these lesions are included in one of several subgroups, for example, thymic tumors, teratomas, or thyroid abnormalities, other less common entities will occasionally be encountered by the practicing surgeon. Likewise, there are variations in the frequency distribution of anterior mediastinal lesions in children as opposed to adults. Management of these individual lesions is outlined.

Thymomas. A review of 169 cases, with particular reference to results of surgical treatment

One hundred sixty-five patients with surgically treated thymoma were followed over 28 years; 73% had myasthenia gravis at presentation. Invasiveness was based on macroscopic findings at operation. Postsurgical radiotherapy or chemotherapy were not routinely used. Overall survival was 84%, 79%, and 65% at 3, 5, and 10 years, respectively. Patients with invasive thymoma survived for a shorter period than patients with noninvasive tumors (67% versus 85% at 5 years); when radical excision was possible, no difference was detectable between the two groups. Patients with subtotally resected or only biopsied invasive thymomas survived 59% and 42% at 5 years, respectively. Lymphoepithelial cases had the worst prognosis of the histologic types considered. Myasthenia gravis did not adversely affect survival. Surgery is the basic treatment of thymomas. Macroscopic invasiveness and degree of excision judged by the surgeon have prognostic value and are reliable criteria of malignancy. Radiotherapy and chemotherapy may be effective, but their use should be limited to controlled trials.

Malignant epithelial tumours of the thymus: survival after radiotherapy

This study describes 26 patients with histologically proven malignant epithelial thymic tumours seen at one radiotherapy centre between 1965 and 1980. Twenty-three patients had mediastinal radiotherapy and the overall 5-year survival rate (corrected for intercurrent death) of this group was 35%. Those patients in which there was complete surgical removal of the tumour had a good prognosis. Where this was not achieved, the prognosis was poor.

Myasthenia gravis: immunohistological heterogeneity in microenvironmental organization of hyperplastic and neoplastic thymuses suggesting different mechanisms of tolerance breakdown

Four samples of thymoma obtained from patients affected by myasthenia gravis have been immunohistologically analysed on cryostat sections using a panel of antisera and monoclonal antibodies specific for antigens which define different stages of intrathymic lymphocyte differentiation and antigens specific for different types of thymic epithelial cells (cortical, medullary). When the thymoma samples were compared to age-matched normal thymuses and hyperplastic thymuses obtained from patients with myasthenia gravis some evident microenvironmental differences could be demonstrated using these reagents. In all the thymoma samples in fact the neoplastic lobules appeared as grossly enlarged cortical-type areas, formed by accumulations of T lymphocytes exhibiting the cortical immature phenotype (TdT+, T6+, etc.) within a network of putatively neoplastic epithelial cells characterized by cortical phenotype as defined by reactivity with various monoclonal antibodies (RFD4-, MR3+). These 'cortical' epithelia showed some abnormal features such as lack or irregular distribution of HLA-DR and enhanced keratin expression. Small areas of 'medullary' differentiation could be observed in 3/4 thymoma samples. In thymic hyperplasia, on the other hand, the cortical areas appeared somewhat compressed (but comparable to those observed in normal age-matched samples) by enlarged medullary areas. The expansion of medullary areas was due to the infiltration of 'peripheral' lymphoid tissue intruding through the extraparenchymal zone and forming organized B and T areas. These observations are discussed in the light of the clinical heterogeneity observed in myasthenia gravis.

Chemotherapy of malignant thymoma. Case report and review of the literature

The authors report the case of a patient with malignant thymoma unresponsive to combination chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP] and cisplatin/VP-16) who subsequently achieved clinical response to continuous daily prednisone. A review of the literature indicates that prednisone and cisplatin are the most active agents in the treatment of malignant thymoma.

Thymoma. The most common anterior mediastinal mass

Thymomas may be discovered during routine evaluation, through reported symptoms, or increasingly, during evaluation for myasthenia gravis. Histologic details of these tumors have little bearing on prognosis or evaluation of malignant potential. Malignancy is determined by evidence of invasion through the tumor capsule at surgery or of distant spread. Complete surgical excision is the mainstay of therapy for both benign and malignant thymoma. Biopsy of anterior mediastinal masses via mediastinoscopy should be avoided because of the risk of violating the thymoma capsule. If the capsule is surgically violated or extracapsular invasion is present, postoperative radiation therapy is indicated.

Primary thymic carcinoma. An unusual case originating in a lymphocytic rich thymoma

A case of thymic carcinoma arising within a lymphocyte rich thymoma is reported. The undifferentiated carcinoma contained cellular elements resembling choriocarcinoma but could be differentiated therefrom by positive staining for prekeratin antigen and an absence of staining for B-HCG antigen utilizing immunohistochemical techniques.

The predominant lymphocyte in most thymomas and in nonneoplastic thymus from patients with myasthenia gravis is the cortical thymocyte

Cell suspensions prepared from 12 specimens of nonneoplastic thymus (6 normal and 6 from patients with myasthenia gravis) and from 17 thymomas were investigated with a panel of monoclonal antibodies. The great preponderance of thymocytes from the 12 nonneoplastic specimens and from 13 of the 17 thymomas (2 of 3 predominantly lymphocytic tumors and 11 of 12 mixed tumors) displayed the surface phenotype of cortical or common thymocytes. These cells formed rosettes with unsensitized sheep erythrocytes (E-rosettes) at both 4 and 37 degrees C, and reacted with the following monoclonal antibodies: OKT1 (thymic and peripheral T cells), OKT6 (common thymocytes), OKT10 (replicating lymphoid cells), OKT11 (sheep cell receptor), and both OKT4 (inducer-helper T cells) and OKT8 (cytotoxic-suppressor T cells). Few B cells (lymphocytes with either immunoglobulin or Ia-like antigen on the cell surface), and few cells with receptors for transferrin and interleukin 2 were detected. Thymocytes from 3 of the 4 remaining thymomas (2 predominantly epithelial tumors and 1 mixed tumor) displayed surface marker characteristics of medullary thymocytes or peripheral T cells; i.e., they were reactive with OKT1, OKT3 (peripheral T cells), OKT11, and either OKT4 or OKT8, and were also E-rosette positive only at 4 degrees C and TdT negative. Thymocytes from the final tumor, a lymphocytic thymoma, exhibited an intermediate phenotype. Thus, almost all mixed (11 of 12) and lymphocytic (2 of 3) thymomas were composed predominantly of cortical thymocytes, while the medullary cell was the rule in the two tumors that were predominantly epithelial.

Remission of invasive thymoma due to chemotherapy. Two patients treated with cyclophosphamide, doxorubicin, and vincristine

Information regarding the effectiveness of chemotherapy in cases of invasive thymoma is limited. Two patients in whom the combination of cyclophosphamide, doxorubicin, and vincristine produced remission of invasive thymoma are described. The durations of remission were eight and seven months, respectively. In both patients, recurrence was observed at the site of bulky disease, and a secondary complete response continuing for 37 months was achieved in one of them with radiation therapy.

Thymoma. A comparative study of clinical stages, histologic features, and survival in 200 cases

Two hundred thymomas, surgically treated between 1955 and 1982 at the Marie Lannelongue Surgical Center, were subjected to statistical analysis, comparing clinical stages and histologic types and relating them to survival. Clinical stages were defined as follows. Stage I: no invasiveness, total excision; Stage II: localized invasiveness (no more than two mediastinal structures); Stage III: largely invasive, with or without distant tumorous grafts, lymph node deposits, or metastases. Four histologic types were retained: (1) spindle or oval cell type thymoma, (2) lymphocyte-rich thymoma, (3) differentiated epithelial thymoma, and (4) undifferentiated epithelial thymoma. Invasiveness remained a major prognostic factor, but the degree of invasion did not affect the survival rate or always justify radical surgery. Thus, the survival rate dropped from 85% at 5 years and 80% at 10 years in noninvasive tumors to 50% and 35%, respectively, in invasive tumors, but without significant difference between moderately invasive Stage II and largely invasive Stage III tumors. Histologic typing indicated a good correlation between the degree of differentiation of the tumors and prognosis. The survival rates were 80% at 5 years and 75% at 10 years for spindle cell type 1 and lymphocyte-rich type 2 thymomas, 75% at 5 years and 50% at 10 years for differentiated epithelial type 3, and nil at 5 years for undifferentiated type 4 thymomas. Although invasiveness often paralleled histologic typing, they appeared as two distinct parameters with separate prognostic significance, particularly in differentiated and undifferentiated epithelial tumors. One hundred five patients had myasthenia gravis and 14 had another autoimmune disease. The associated syndromes were no longer an adverse factor in the prognosis of thymoma.

Recurrence of thymoma: clinicopathological features, therapy, and prognosis

Factors influencing the recurrence or persistence of thymoma after therapy were investigated in 127 patients with thymoma, including 75 with thymoma and myasthenia gravis. The rate of recurrence or persistence was 19% (24 of 127 patients) overall, 11% (8 of 75 patients) in myasthenic thymoma, and 31% (16 of 52 patients) in nonmyasthenic thymoma. The more advanced the clinical stage, the higher the rate of recurrence or persistence. The recurrence/persistence rate for patients with the same clinical stage was higher in those with nonmyasthenic thymoma (8% in Stage I, 11% in Stage II, 36% in Stage III, and 75% in Stage IV) than in those with myasthenic thymoma (0 in Stage I, 13% in Stage II, 18% in Stage III, and 20% in Stage IV). The prognosis for patients having subtotal resection of tumor was good in myasthenic thymoma (recurrence/persistence rate, 17%) in contrast with nonmyasthenic thymoma (recurrence/persistence rate, 78%). These results suggest that nonmyasthenic thymoma is more malignant than myasthenic thymoma. Postoperative radiotherapy was effective in preventing the recurrence or persistence of thymoma after therapy.

Thymoma and thymic carcinoma. Relation of thymoma epithelial cells to the cortical and medullary differentiation of thymus

Based on the light microscopical features of normal thymic epithelial cells, human thymoma was divided in different types, namely cortical, medullary, and mixed ones, according to the epithelial cell (EC) type. Lymphoid cell populations with morphological features of either cortical or medullary thymocytes were found according to different types of EC in thymoma. The histological variation of the different types of thymoma are demonstrated. In a retrospective study of 58 thymomas and 13 thymic carcinomas, malignant invasive character as well as the occurrence of myasthenia gravis were both found to be related to the neoplastic proliferation of the cortical epithelial cells, whereas in the usual mixed type of thymoma and the medullary type no gross invasion or metastases were noticed. These results are discussed in view of recent concepts and immunological findings of thymus microarchitecture.

Myasthenia gravis in otolaryngological practice

A retrospective study of 48 unselected patients with myasthenia gravis was undertaken to evaluate the head and neck manifestations of this disease and to examine the role of the otolaryngologist in diagnosis and management. Oropharyngeal features were found in 56% of patients at presentation. In 20 the initial complaint was of one or more symptoms referable to the upper aerodigestive tract, whilst in 9 (18.8%) these were the only symptoms. The importance of maintaining a high index of clinical suspicion is emphasized, as the early muscle weakness is invariably mild and fluctuant. Contemporary aspects of the aetiology, diagnosis and management are considered. Particular attention is focused on the characteristics of the stapedius reflex in this disorder, as this is probably the most sensitive objective test for assessing defective neuromuscular transmission.

The fine needle aspiration cytology of mediastinal lesions

Fine needle aspiration cytology was performed in 19 mediastinal lesions. Of seven malignant neoplasms six were correctly diagnosed as malignant and in five of these accurate tumor classification was possible. Of the 12 benign lesions only four cases, all thymomas, could be diagnosed cytologically. No false-positive diagnoses of malignancy were made. The only complication of the procedure was minor pneumothorax in two patients. In five cases the use of the technique spared the patient from more invasive diagnostic procedures; in several others, valuable information was obtained prior to surgery.

Thymolipoma in association with myasthenia gravis

Among 72 thymic tumors that were examined we have found five (7.5%) thymolipomas. Two of these patients have had clinical symptoms. One, a five-year-old boy, has had an erythrocyte hypoplasia as well as a hypogammaglobulinemia. The other patient, a 56-year-old man, has had myasthenia gravis. This case is the second in the world literature in which a thymolipoma is associated with symptoms of myasthenia gravis. The clinical, radiologic, and histopathologic findings and the pathogenesis of thymolipoma are discussed.

Metastasising thymoma

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Metastatic thymoma with myasthenia gravis: complete remission with combination chemotherapy

A 29-year-old male developed myasthenia gravis 29 months after resection of a "benign" mediastinal thymoma. Metastatic thymoma was found in the pleura 45 months after the initial surgical resection. Combination chemotherapy with cyclophosphamide and doxorubicin produced a complete remission of the metastatic thymoma which has continued for 13 months. Concurrently, there has been a marked increase in neuromuscular function.

Treatment and prognosis of thymoma: a review of 25 cases

Experience of 25 patients with thymoma is reported. Based on the presence or absence of gross invasion 17 tumors were regarded as benign, 8 as malignant. All patients were operated on. Twenty-two had a complete excision, 2 a palliative excision, and 1 a biopsy only. Five patients received post-operative radiotherapy and 2 patients were given cytotoxic chemotherapy. None of the 17 patients with a benign thymoma had a recurrence or death due to thymoma during the follow-up. The five- and ten-year survival rates for malignant thymoma were 50% and 17%, respectively. Excision is the treatment of choice for all thymomas, since the prognosis for benign tumor is excellent and the malignancy can only by determined at exploration. Post-operative radiotherapy seems to be indicated in malignant thymoma. Myasthenia gravis and histologic features of thymoma have some value in predicting prognosis.

Two-dimensional echocardiographic findings of cardiovascular involvement by invasive thymoma

Two-dimensional echocardiographic features are described in a patient with invasive thymoma. In the present study, we emphasize that two-dimensional echocardiography is useful in detecting both the extent of thymoma itself and its invasion to the pericardium and pulmonary artery.

Long-lasting response to cis-platinum in recurrent malignant thymoma: case report

A patient who had received irradiation for inoperable invasive thymoma was treated with cis-platinum after mediastinal and endothoracic recurrence two years from diagnosis. A quick and long-lasting response was observed, which is still present. Systematic phase II trials with cis-platinum in invasive thymoma are suggested.

Follow-up study of thymomas with special reference to their clinical stages

Follow-up data were obtained for 96 cases of thymoma. The one-year survival rate was 84.3%, the three-year 77.1%, the five-year 74.1%, and the ten-year 57.1%. The five-year survival rate of total resection group was 88.9%; that of non-radically treated group was 44.4%. Clinical stages were defined: Stage I--macroscopically encapsulated and microscopically no capsular invasion; Stage II--1. macroscopic invasion into surrounding fatty tissue of mediastinal pleura, or 2. microscopic invasion into capsule; Stage III--macroscopic invasion into neighboring organ; Stage IVa--pleural or pericardial dissemination; Stage IVb--lymphogenous or hematogenous metastasis. Five-year survival rates of each clinical stage were 92.6% in Stage I, 85.7% in Stage II, 69.6% in Stage III, and 50% in Stage IV. Recurrence after total resection was found in six of 69 cases. Seven of 13 patients treated by subtotal resection survived more than five years with postoperative radiotherapy.