An electronic endoscope comprising: a hub; a shaft extending from the hub, the shaft having an outer diameter; an expandable distal tip extending from a distal portion of the shaft; an image sensor within the distal tip and having a field of view external from the electronic endoscope; an illuminating element within the distal tip and configured to emit light within the field of view of the image sensor; a working channel extending within the shaft and distal tip, the working channel comprising a variable profile portion within the distal tip, wherein the variable profile portion of the working channel is adapted to change from a generally noncircular cross-sectional shape to a different cross-sectional shape to accommodate passage of a tool, wherein the distal tip has a diameter greater than said outer diameter of the shaft when the variable profile portion of the working channel has the different cross-sectional shape, and wherein the working channel is adapted to accommodate passage of the tool through a proximal portion of the shaft without increasing an overall diameter of the proximal portion of the shaft; and a second channel extending within the shaft and distal tip, the second channel comprising a variable profile portion within the distal tip, wherein the variable profile portion of the second channel is adapted to change to a different shape to accommodate passage of a fluid through the second channel, wherein the distal tip has a diameter greater than] said outer diameter of the shaft when the variable profile portion of the second channel has the different shape, wherein the second channel is adapted to accommodate passage of the fluid through the proximal portion of the shaft without increasing the overall diameter of the proximal portion of the shaft, and characterised in that the working channel and the second channel are distributed circumferentially about the image sensor, by which the image sensor is disposed between the working channel and the second channel. a hub; a shaft extending from the hub, the shaft having an outer diameter; an expandable distal tip extending from a distal portion of the shaft; an image sensor within the distal tip and having a field of view external from the electronic endoscope; an illuminating element within the distal tip and configured to emit light within the field of view of the image sensor; a working channel extending within the shaft and distal tip, the working channel comprising a variable profile portion within the distal tip, wherein the variable profile portion of the working channel is adapted to change from a generally noncircular cross-sectional shape to a different cross-sectional shape to accommodate passage of a tool, wherein the distal tip has a diameter greater than said outer diameter of the shaft when the variable profile portion of the working channel has the different cross-sectional shape, and wherein the working channel is adapted to accommodate passage of the tool through a proximal portion of the shaft without increasing an overall diameter of the proximal portion of the shaft; and wherein the distal tip has a diameter greater than said outer diameter of the shaft when the variable profile portion of the working channel has the different cross-sectional shape, and wherein the working channel is adapted to accommodate passage of the tool through a proximal portion of the shaft without increasing an overall diameter of the proximal portion of the shaft; and a second channel extending within the shaft and distal tip, the second channel comprising a variable profile portion within the distal tip, wherein the variable profile portion of the second channel is adapted to change to a different shape to accommodate passage of a fluid through the second channel, wherein the distal tip has a diameter greater than] said outer diameter of the shaft when the variable profile portion of the second channel has the different shape, wherein the second channel is adapted to accommodate passage of the fluid through the proximal portion of the shaft without increasing the overall diameter of the proximal portion of the shaft, and characterised in that the working channel and the second channel are distributed circumferentially about the image sensor, by which the image sensor is disposed between the working channel and the second channel. wherein the distal tip has a diameter greater than] said outer diameter of the shaft when the variable profile portion of the second channel has the different shape, wherein the second channel is adapted to accommodate passage of the fluid through the proximal portion of the shaft without increasing the overall diameter of the proximal portion of the shaft, and characterised in that the working channel and the second channel are distributed circumferentially about the image sensor, by which the image sensor is disposed between the working channel and the second channel.