Documenting lymphangitic metastases to the lungs may be therapeuticall
y important. Several techniques have been described to this end. Sputu
m cytology, the least invasive and expensive, is the most available. I
t has a role that may be overlooked but that should be emphasized, sin
ce abundant malignant cells in sputum may be associated with this patt
ern of tumor spread. This case is the first, to the authors' knowledge
, in which the pathologic findings associated with malignant cells in
lymphangitic carcinomatosis were demonstrated in sputum in the absence
of tumor mass invasion of large airways.