Case Report: A very rare case of a Pleural Effusion revealing Multiple Myeloma [version 3; peer review: 1 approved, 2 approved with reservations] oleh Marwa Kacem, Samia Essbaa, Chiraz Aichaouia, Samira Mhamdi, Selsabil Daboussi, Asma Saidane, Issam Msakni, Hela Ghedira, Zied Moatemri, Faten Gargouri