In the Japanese word for Non-Hodgkin's Lymphoma, where does the パ before 腫 come from?
Lymph = リンパ
Lymphoma = リンパ腫
There is nothing mysterious about it.
user27280 has the right of it.
Some additional information:
- リンパ is historically found in kanji as 淋巴.
- The term is a borrowing from Dutch lympha (now archaic, replaced by lymf[e]), in turn from Latin lympha ("pure water"), in turn from Ancient Greek νύμφη (nymphe, "bride; spring water"), and also cognate with English nymph.
- My sources (Daijirin, Daijisen, Shogakukan's Kokugo Dai Jiten) don't give enough detail to suss out when this was borrowed. However, given the 淋巴 kanji spelling and the archaic Dutch etymon (root), I'm inclined to think that this was an early borrowing from the 1600s (compare 煙草 (tabako), a similar early borrowing that has nativized kanji spellings).