Diagnosis and treatment of malignant PEComa tumours

PEComa (PEC tumours; perivascular epithelioid cell tumours) is a family of rare tumours of mesenchymal origin, consisting of epithelial perivascular cells expressing melanocytic and myioid markers. This group includes benign tumours — such as angiomyolipoma (AML) of the kidney, and poorly differentiated malignant PEComa tumours with potential for an aggressive clinical course, which is the main focus of this review. PEComas are most often diagnosed in middle-aged women as extensive tumours located in the abdominal cavity or pelvis, manifesting as pain and complaints related to pressure on nearby organs. PEComa tumours should be differentiated from gastrointestinal stromal tumours (GIST), leiomyosarcoma, melanoma metastasis, chromophobic renal cell carcinoma, clear cel sarcoma, and other clear cell component tumours. Somatic inactivating mutations within the TSC1/TSC2 genes, resulting in excessive activation of the mTORC1 complex, are characteristic for this group of tumour. Recently, a separate PEComa subgroup has been distinguished, characterised by the presence of the TFE3 gene fusion, which also causes increased activity of the mTOR signalling pathway. Negative prognostic factors that indicate an increased risk of PEComa malignant biology are most often: tumour size > 5 cm, increased cytological and nuclear atypia, infiltration of surrounding tissues and blood vessels, presence of necrosis, and high mitotic activity. Radical resection remains the primary treatment method for PEComas because these tumours are characterised by high resistance to radiation and chemotherapy. In the case of locally advanced or metastatic disease, only single reports of short-term responses to palliative chemotherapy containing doxorubicin, gemcitabine, or ifosfamide are available in the literature. There are an increasing number of reports, in the form of several case reports and a few retrospective analyses, about the potential effectiveness of using mTOR inhibitors in unresectable cases. These drugs result in a reduction in primary tumour size and metastasis, as well as symptom relief, with controllable side effects. Unfortunately, case reports of complete resistance to mTOR inhibitor therapy are also available.PEComa (PEC tumours; perivascular epithelioid cell tumours) is a family of rare tumours of mesenchymal origin, consisting of epithelial perivascular cells expressing melanocytic and myioid markers. This group includes benign tumours — such as angiomyolipoma (AML) of the kidney, and poorly differentiated malignant PEComa tumours with potential for an aggressive clinical course, which is the main focus of this review. PEComas are most often diagnosed in middle-aged women as extensive tumours located in the abdominal cavity or pelvis, manifesting as pain and complaints related to pressure on nearby organs. PEComa tumours should be differentiated from gastrointestinal stromal tumours (GIST), leiomyosarcoma, melanoma metastasis, chromophobic renal cell carcinoma, clear cell sarcoma, and other clear cell component tumours. Somatic inactivating mutations within the TSC1/TSC2 genes, resulting in excessive activation of the mTORC1 complex, are characteristic for this group of tumour. Recently, a separate PEComa subgroup has been distinguished, characterised by the presence of the TFE3 gene fusion, which also causes increased activity of the mTOR signalling pathway. Negative prognostic factors that indicate an increased risk of PEComa malignant biology are most often: tumour size > 5 cm, increased cytological and nuclear atypia, infiltration of surrounding tissues and blood vessels, presence of necrosis, and high mitotic activity. Radical resection remains the primary treatment method for PEComas because these tumours are characterised by high resistance to radiation and chemotherapy. In the case of locally advanced or metastatic disease, only single reports of short-term responses to palliative chemotherapy containing doxorubicin, gemcitabine, or ifosfamide are available in the literature. There are an increasing number of reports, in the form of several case reports and a few retrospective analyses, about the potential effectiveness of using mTOR inhibitors in unresectable cases. These drugs result in a reduction in primary tumour size and metastasis, as well as symptom relief, with controllable side effects. Unfortunately, case reports of complete resistance to mTOR inhibitor therapy are also available

Diagnosis and treatment of rhabdomyosarcomas

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma. The primary tumor is most commonly localized in the head and neck, the urogenital system, or the limbs. Classification by the World Health Organization has distinguished four histopathological RMS subtypes: embryonal, alveolar, pleomorphic, and spindle cell/sclerosing. Differential diagnosis of RMS includes melanoma, malignant neoplasm of peripheral nerve sheaths, liposarcoma, and PEComa. Among typical cytogenetic changes in RMS are chromosomal translocations t(2;13)(q35;q14) and t(1;13) (p36;q14). They lead to the formation of fusion genes that have a prognostic value. In the course of RMS, changes may also be present in signaling pathways, including RAS-PI3K, Wnt/b-catenin, receptor tyrosine kinase pathways, and myogenesis regulation. In 30% of patients at the time of diagnosis of RMS, distant metastases are present, most commonly to lungs, lymph nodes, bones, and bone marrow. Treatment of patients with RMS requires a multidisciplinary approach, and steadily perfected diagnostic techniques contribute to the individualization of therapeutic strategies. Optimal treatment of localized RMS is based on surgery combined with radiotherapy and chemotherapy. If distant metastases are present, the basic therapeutic method is multidrug chemotherapy, most frequently based on vincristine, dactinomycin, ifosfamide/cyclophosphamide, and etoposide. Despite intensive treatment, the 5-year survival index for RMS is not greater than 50%. There are still no unequivocal guidelines concerning the treatment in patients with local or distant recurrences

Zalecenia Polskiej Grupy Mięsakowej w odniesieniu do postępowania diagnostyczno-terapeutycznego oraz kontroli u chorych na neurofibromatozę typu 1 (NF1) oraz związanego z nią złośliwego nowotworu osłonek nerwów obwodowych

Type 1 neurofibromatosis (NF1 syndrome in von Recklinghausen’s disease) is inherited as an autosomal dominant disease, caused by mutations in the NF1 gene encoding the neurofibromin protein. NF1 patients are at an increased risk of the develop­ment of a malignant neoplasm and their life span is shorter by 20 years than that of the general population. National Institute of Health (NIH) criteria make a diagnosis possible from about 4 years of age. Examination of children and adults should encom­pass a physical and a subjective component, but also next-generation sequencing (NGS) genetic analysis, histopathological examination of skin lesions, neurological, ophthalmological and radiological examination. If a malignant peripheral nerve sheath tumor (MNPST) is diagnosed in a patient with NF1, the therapeutic procedure should not differ from the general principles of treating soft tissue sarcomas. Patients from the high risk group should be monitored at least once a year, the remaining patients once every 2–3 years by a specialized medical team, and every year by their primary physicians, internal medicine specialists and dermatologists. Patients should have access to genetic counselling.Neurofibromatoza typu 1 (zespół NF1 w chorobie Recklinghausena, nerwiakowłókniakowatość typu 1), jest dziedziczona au­tosomalnie dominująco, a odpowiadają za nią mutacje genu NF1 kodującego białko neurofibrominy. Pacjenci z NF1 są naraże­ni na zwiększone ryzyko rozwoju nowotworu złośliwego i żyją około 20 lat krócej niż populacja ogólna. Kryteria National Insti­tute of Health (NIH) umożliwiają postawienie diagnozy już około 4 roku życia. Badanie dzieci i dorosłych powinno objąć bada­nie przedmiotowe i podmiotowe, ale też badanie genetyczne techniką sekwencjonowania nowej generacji (NGS), badanie histopatologiczne zmian skóry, badanie neurologiczne, okulistyczne i radiologiczne. W przypadku postawienia roz­poznania złośliwego nowotworu osłonek nerwów obwodowych (malignant peripheral nerve sheath tumor – MPNST) u chorego na NF1 postępowanie terapeutyczne nie powinno odbiegać od ogólnych zasad leczenia mięsaków tkanek miękkich. Pacjenci z grupy wysokiego ryzyka powinni być monitorowani przynajmniej raz w roku, pozostali – raz na 2–3 lata – przez zespół lekarzy specjalistów, a co roku przez lekarzy podstawowej opieki zdrowotnej (POZ), chorób wewnętrznych i dermatologów. Pacjentom należy zapewnić poradnictwo genetyczne