Answer: Dirofilaria sp., most likely D. immitis, given the location in the lung.
As Blaine pointed out, this case is unusual in that it features an adult rather than larval worm, as evidenced by the presence of reproductive organs. While it's not uncommon to see adult Dirofilaria in subcutaneous lesions (e.g. caused by D. tenuis), it's very uncommon (but not unheard of) to see adults in the lung. Some of the diagnostic features are highlighted in the image below.
Thanks to everyone who gave the whole slide imaging technology a 'whirl', even if histopathology is not your area of expertise.