Although papillary endothelial hyperplasia may occur at almost any site, one of the most common sites is the hand. It is generally regarded as a reactive vascular proliferation i.e. exuberant form of organizing thrombus. Diagnosis of Masson tumor can be challenging due to its close clinical, radiological and even histopathological resemblance to angiosarcoma. We present seven cases of Masson tumor of the hand; wanting to reveal its nature using new vascular markers and discuss the treatment options and expected outcomes, present clinical and radiological features that may aid diagnosis and also offer treatment plans. A multicenter retrospective study was performed between January 2014 and November 2019. Immunohistochemical stains of Glut1, WT1, ERG, CD31 and alpha smooth muscle actin (ASMA) were performed on each cases. We found seven cases during the examined period. 4 out of 7 cases were women. All lesions occurred in the hands. 3 out of 7 cases appeared in a previously present vascular malformation. All cases were treated with surgical excision and the diagnosis of papillary endothelial hyperplasia was made by histology. Pre-operative testing (radiograph/MRI/US/fine needle aspiration biopsy) did not suggest the diagnosis of Masson tumor; however, aspiration cytology could rule out malignancy. The proliferative endothelial cells proved to be Glut1 negative and WT1 positive and the accompanying pericytic cells were ASMA positive in all cases. Though Masson tumor is a rare vascular lesion in the hand among other vascular tumors, it should be considered in the differential diagnostics even in the case of previously existing vascular malformation. WT1 positivity of the endothelial cells and the accompanying pericytic cells raises the question whether the initially reactive endothelial proliferation may transform into a true benign vascular tumor.

A Rhodococcus equi ritka patogén, amely főként gyengült immunrendszerű vagy immunszupprimált betegekben okoz fertőzést. Esetbemutatásunkban Rhodococcus equi által okozott nagyízületi endoprotézis körül kialakult fertőzést mutatunk be, amelynek leírására még nem volt példa a nemzetközi irodalomban. A 88 éves férfi beteget láz és jobb oldali csípőfájdalom miatt vettük fel klinikánkra. A beteg anamnézisében több, mindkét oldalt érintő csípőműtét szerepelt, és a jobb oldalon aszeptikus lazulás miatt korábban revíziós arthroplastica is történt. Ismert betegségei között szerepelt cukorbetegség, diabeteses nephropathia, valamint korábbi stroke miatt bal oldali hemiplegia, azonban kifejezett immunszuppresszió nem. A képalkotó vizsgálatok a jobb oldali csípőprotézis komponenseit stabilnak mutatták, az ízületi punkcióból pedig Rhodococcus equi tenyészett ki. A betegnek azonnali feltárást és a protézis kö-rüli terület tisztítását javasoltuk, amit visszautasított. Konzervatív kezelést, parenteralis antibiotikum-terápiát kezdtünk. A beteg gyulladásos paraméterei csökkentek, fájdalma megszűnt. Esettanulmányunk célja, hogy a nagyízületi protézisek szeptikus komplikációi kapcsán felhívjuk a figyelmet a ritka patogének növekvő szerepére. Orv Hetil. 2017; 158(27): 1071-1074. Kulcsszavak: Rhodococcus equi, periprotetikus fertőzés, ritka kórokozó Periprosthetic joint infection caused by Rhodococcus equi Case reportRhodococcus equi is a rare pathogen in humans causing infections mostly in immunocompromised hosts. We present the first case of periprosthetic joint infection caused by Rhodococcus equi. An 88-year-old male patient was referred to our clinic with a history of fever and right hip pain. The patient had multiple hip surgeries including total joint arthroplasty and revision for aseptic loosening on the right side. He was immunocompetent, but his additional medical history was remarkable for diabetes mellitus, diabetic nephropathy and stroke with hemiplegia resulting in immobilization. Radiography showed stable components, joint aspirate yielded Rhodococcus equi. Irrigation and debridement was proposed, but the patient refused any surgical intervention. Therefore antibiotic therapy was administered. At the last follow-up the patient is free of complaints but the C-reactive protein level is still elevated. This case illustrates the possible role of Rhodococcus equi in medical device-associated infections.