Eleven patients with localized lymphoid nodules of the lung (LLN) were seen at the Mount Sinai Hospital from 1962-1981. The diagnosis of
pseudolymphoma was made in six instances based on the following criteria: (1) solitary or multiple nodules discovered on chest roentgenograms composed of cytologically benign lymphoid cells (small lymphocytes); (2) polymorphic character of the infiltrate, including plasma cells, histiocytes and monocytes; and (3) presence of germinal centers in the lesion. Five lesions were classified as
lymphomas and exhibited: (1) solitary or multiple nodules composed of atypical lymphoid cells; (2) absence of germinal centers; (3) lack of mediastinal lymph node involvement. Bronchial and/or pleural infiltration by lymphoid cells was present in
lymphomas as well as in
pseudolymphomas. Five lesions were studied with immunofluorescent techniques for the presence of intracytoplasmic
immunoglobulins and in one
pseudolymphoma, lymphocyte marker studies were performed. The procedures were not useful in separating benign from malignant lesions. All patients underwent surgery; three with
lymphoma and one with
pseudolymphoma received
adjuvant chemotherapy. Patients were followed post surgically for up to 13 years. None of the six patients with
pseudolymphoma died as a result of their lesions but two had either recurrences or developed extrapulmonary lymphoid lesions. All five
lymphoma patients did well. Only one died while on
chemotherapy with
invasive pulmonary aspergillosis but no
tumor. One-hundred and sixty-seven reported cases from the literature are analyzed. Pulmonary
pseudolymphomas do not necessarily follow a benign course and
malignant lymphomas limited to the lungs do not usually undergo progressive disease. Present pathologic criteria do not allow prediction of recurrence or progression of disease and are not acceptable for determining the advocacy of
chemotherapy in patients with LLN.