Multivesicular bodies in alveolar macrophages are generally roundish, not always perfectly round, but more round than elongated.  Here are two multivesicular bodies-late endosomes with inclusions which are presumed to be E2 left over from liquid breathing (MVB/LE/PFC) which have lots of protein enzyme content (way more in a volume ratio than E2) and have an elongated shape.  There is a large reaction to the E2 droplets in terms of enzyme production.  So the ratio of perfluorochemical to protein in the lysosomal structures might give a clue as to the characteristics of “export” or “offgassing” of these liquids from the body. The size of the smallest E2 particle in these micrographs is slightly larger in diameter than a ribosome (taken from the same micrograph and enlarged similarly (two insets at right are from the respective boxes top and bottom in the portion of the alveolar macrophage, and there are many MVB, different sizes and many E2 droplets with different amounts of enzyme.  I would guess that the smaller droplets are more enzyme packed than the larger droplets — equating to residence time within the macrophage cytoplasm???