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Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.

Thymic carcinomas (TC) are approximately 10 times less prevalent than thymomas but of high clinical relevance because they are more aggressive, less frequently resectable than thymomas and usually refractory to classical and targeted long-term treatment approaches. Furthermore, in children and adolescents TC are more frequent than thymomas and particularly in this age group, germ cell tumors need to be a differential diagnostic consideration. In diagnostic terms pathologists face two challenges: a), the distinction between thymic carcinomas and thymomas with a similar appearance and b), the distinction between TC and histologically similar metastases and tumor extensions from other primary tumors. Overcoming these diagnostic challenges is the focus of the new WHO classification of thymic epithelial tumors. The objectives of this review are to highlight novel aspects of the WHO classification of thymic carcinomas and to address therapeutically relevant diagnostic pitfalls.

Introduction: Patients with pleural thymoma spread (Masaoka stage IV a) should be treated within a multimodal treatment regime. However, the extent of local surgical resection to achieve optimal tumour control remains controversial., Patients and Methods: Prospective analysis between September 2008 and April 2013 of all patients with a Masaoka stage IV a thymoma, who underwent radical pleurectomy/decortication (P/D) followed by hyperthermic intrathoracic chemotherapy (HITHOC)., Results: A total of 11 patients (male n = 7; mean age 46.5 ± 11.4 years) with a primary stage IV a thymoma (n = 3) or thymoma with pleural relapse (n = 8) were included after successful transsternal thymoma resection. WHO histological classification was: B1 n = 1, B2 n = 6, B3 n = 3 and C n = 1. A radical P/D (5/11; 45 %) was extended with resection of the pericardium and diaphragm in 6/11 (55 %) patients. After surgical resection (91 % complete macroscopic R0/R1-resection) the HITHOC with cisplatin (100 mg/m2 body surface area (BSA) n = 7; 150 mg/m2 BSA n = 4) was performed for one hour at 42 °C. Operative revision was necessary in two patients (chylo- and hematothorax) with one patient also requiring temporary renal replacement therapy due acute renal failure (cisplatin 150 mg/m2 BSA). 30-day mortality was 0 %. Local recurrence (pulmonary n = 1, paravertebral n = 2) was documented in 3/10 (30 %) patients after R0/R1 resection. After a mean follow-up of 23 months the overall median survival was 27 months and 82 % (9/11) patients are still alive at the end of the study period., Conclusions: Masaoka stage IV a thymoma could be safely treated with lung-sparing radical P/D and HITHOC with cisplatin in a multimodality treatment regime. Early results with respect to recurrence and survival are encouraging, but further studies are warranted and we have to await long-term results., (Georg Thieme Verlag KG Stuttgart · New York.)

Neuromuscular diseases accompanying thymoma include myasthenia gravis, polymyositis, dermatomyositis, and neuromyotonia. Usually 50% of patients with thymoma develop myasthenia gravis. However, only 5% show polymyositis as an accompanying paraneoplastic phenomenon. We report the case of a patient with thymoma showing myasthenia gravis as well as polymyositis. Due to the simultaneous occurrence of these paraneoplastic diseases, the criteria for exact diagnosis (serum creatine kinase, EMG, ocular involvement) overlap. This diagnostic dilemma can appreciably complicate the therapeutic approach.

Thymoma is a rare epithelial tumor of the thymus, but the most common malignancy in the anterior mediastinum. A unique feature is its association with paraneoplastic syndromes, in particular myasthenia gravis. According to the WHO classification 6 histologic types of thymic epithelial tumors can be discriminated. Tumor stage according to MASAOKA is the most important prognostic factor. Non-invasive tumors (stage I) are usually completely resected and no further therapy is warranted. For incompletely resected tumors and locally advanced invasive thymomas (stage Ill-IV) postoperative radiotherapy with 50-60 Gy is advisable. Chemotherapy, preferably with Cisplatinum, is indicated with inoperable thymomas or metastatic disease. In general thymomas have a fair prognosis even in advanced stage. Long term follow-up is mandatory up to 10 years.

Up to 40% of patients with malignant thymoma suffer from paraneoplastic symptoms (90% myasthenia, 10% other symptoms). A 55-year-old patient developed ascending symmetrical sensorimotor tetraparesis. A malignant thymoma without metastases was diagnosed 6 months later. Despite thymectomy followed by radiation and high-dose corticosteroid therapy, the polyneuropathy progressed. Six months after onset, the patient was bound to a wheelchair. Immunosuppressive therapy with cyclophosphamide was initiated, leading to marked remission. After ten cycles, the patient was able to walk independently with walking aids. After the sixth and tenth cycle, respectively, attempts to discontinue immunosuppression led to relapse. In several diagnostic workups, however, there was no tumour relapse. After 13 cycles, cyclophosphamide was replaced by immunoglobulins (0.4 g/kg per day i.v. for 5 days/month) due to progressive renal failure. The patient died just before the second course of this treatment. In conclusion, in the differential diagnosis of rapidly progressive polyneuropathy, a malignant thymoma should be considered, even in the absence of myasthenia. Immunosuppression with cyclophosphamide resulted in amelioration of symptoms in this patient.

A 40-year old woman with an invasive thymoma and myasthenia gravis is described in this article. Chest-x-ray, CT and MRI of the mediastinum could not offer definite results on tumour malignancy. Radical surgical removal was the consequence. This revealed a tumour infiltration of the pleura and pericardium; hence an adjuvant irradiation must have been performed. Mestinon--treatment was afterwards gradually reduced.

The most important prognostic determinants of the thymomas are the gross findings at operation (equal to the presence or absence of gross invasion of adjacent tissue) and the presence or absence of the thymoma-associated systemic disease, particulary myasthenia gravis. The histologic type of thymoma had no proof value in predicting prognosis with the exception of the so-called atypical thymomas. Thirty-four of 57 patients with thymomas were females and 23 males. The tumors in 40 cases were non-invasive thymomas, and in 17 cases the tumour were invasive of adjacent tissue. 35.1 percent of patients were asymptomatic, the tumours being discovered on roentgenograms done on a routine basis or for an unrelated porpose. 40.3 percent of patients have had a thymoma-associated systemic disease. The most common presenting symptoms were related to myasthenia gravis (26.3%). The 5-year survival rate was 90 percent for non-invasive thymomas without myastenia gravis and 50 percent for invasive thymomas. The 5-year survival rate for patients with myasthenia gravis and encapsulated (non-invasive) thymomas was approximately 60 percent, whereas that for invasive thymomas with myasthenia gravis was 40 percent. The primary form of therapy for all thymomas is the surgical excision. In cases with invasive and/or metastasizing thymomas, postoperative radiation and adjuvanted chemotherapy is indicated, but in most series, the longterm results of this form of therapy are discouraging.