A tissue containment bag, comprising a first opening and a second opening interconnected by a sidewall of flexible material, the sidewall defining a first interior compartment configured for receiving a tissue specimen through the first opening into the first interior compartment ; the sidewall forming an elongated hollow, sleeve-like neck extension defining a second interior compartment having a proximal end interconnected with the first interior compartment and a distal end interconnected with the second opening ; the second opening being in fluidic communication with the second interior compartment ; the second interior compartment being in fluidic communication with the first interior compartment and the first interior compartment being in fluidic communication with the first opening ; the sidewall at the first interior compartment having a width perpendicular to a first longitudinal axis defined by a radial plane of the first opening when the bag is in undeflected configuration and a length along the first longitudinal axis; the neck extension having a width perpendicular to a second longitudinal axis defined by a radial plane of the second opening when in undeflected configuration and a length along the second longitudinal axis; and the width of the neck extension being smaller than the width of the first interior compartment, the tissue containment bag being characterized in that the neck extension includes a sealing mechanism for sealing off the second opening when the tissue containment bag is ready for removal from an incision or a body orifice; the sealing mechanism comprising a first pocket having a first pocket mouth and a second pocket having a second pocket mouth , wherein the first and second pockets are connected to an outer surface of the neck extension such that the first pocket mouth faces the second pocket mouth . the sidewall defining a first interior compartment configured for receiving a tissue specimen through the first opening into the first interior compartment ; the sidewall forming an elongated hollow, sleeve-like neck extension defining a second interior compartment having a proximal end interconnected with the first interior compartment and a distal end interconnected with the second opening ; the second opening being in fluidic communication with the second interior compartment ; the second interior compartment being in fluidic communication with the first interior compartment and the first interior compartment being in fluidic communication with the first opening ; the sidewall at the first interior compartment having a width perpendicular to a first longitudinal axis defined by a radial plane of the first opening when the bag is in undeflected configuration and a length along the first longitudinal axis; the neck extension having a width perpendicular to a second longitudinal axis defined by a radial plane of the second opening when in undeflected configuration and a length along the second longitudinal axis; and the width of the neck extension being smaller than the width of the first interior compartment, the tissue containment bag being characterized in that the neck extension includes a sealing mechanism for sealing off the second opening when the tissue containment bag is ready for removal from an incision or a body orifice; the sealing mechanism comprising a first pocket having a first pocket mouth and a second pocket having a second pocket mouth , wherein the first and second pockets are connected to an outer surface of the neck extension such that the first pocket mouth faces the second pocket mouth . <EOS>