[Combined histiocytosis of the Langerhans group (Langerhans cell histiocytosis and Erdheim-Chester disease) in a 64-year-old man with BRAF and NRAS mutations: a case report]. / Histiocitosis combinada de tipo Langerhans (Histiocitosis de células de Langerhans y enfermedad de Erdheim-Chester) en varón de 64 años con mutaciones en BRAF y NRAS: a propósito de un caso.

We present a case of a 64-year-old male with a history of Crohn's disease who presented with an episode of acute abdominal pain. He was being investigated for a dermatological lesion. A skin and lung biopsy both revealed histiocytosis of the "L" (Langerhans) group. The skin biopsy showed a proliferation of histiocytic cells expressing Langerin, CD1a and S100 and the molecular study was positive for the BRAF p.V600E mutation. In the lung biopsy, a proliferation of histiocytic cells was found, which were positive for CD68 and S100 and negative for Langerin and CD1a; mutations in NRAS c.38G>A in exon 2 (p.G13D) were also detected.

ETV6-NTRK3-positive parotid mammary analogue secretory carcinoma: a case report.

INTRODUCTION: Mammary analogue secretory carcinoma (MASC) is a recent discovered entity of salivary glands tumors, reported for first time in 2010. The presence of a translocation encodes the ETS variant transcription factor 6-neurotrophic tyrosine receptor kinase (ETV6-NTRK3) gene fusion differences MASC from other tumors. CASE PRESENTATION: A 68-year-old male showed a non-painful right parotid enlargement, came from dermatology service, and followed by some facial squamous cell carcinomas. A computed tomography (CT) scan showed a 1.7×1.6 cm right parotid enlargement in superficial lobe. The patient underwent a right superficial parotidectomy. The final pathology confirmed the presence of ETV6-NTRK3-positive MASC. Complete right deep parotidectomy and functional cervical emptying were performed. DISCUSSIONS AND CONCLUSIONS: It is necessary to establish an appropriated differential diagnosis between salivary gland tumors. MASC is a low-grade malignancy cancer that sometimes can evolve to a high-grade tumor that might produce local and distance dissemination. Most times, these tumors are only treated by surgical resection and evaluating by a multidisciplinary team the need of more treatments. In our case, the patient showed a primary parotid tumor, removed surgically with free edges, and being identified as MASC. We decided to underwent neck dissection and discovered a second MASC focus on cervical salivary gland; however, there was no nodal dissemination. The patient remains disease-free after 14 months from last surgery. It is important to keep studying genetic therapy targets to ETV6-NTRK3 to obtain a new therapy line to treat those cases that require.