The primary multiple lung cancer observed in 3% of cancer patients is often characterized by peculiar clinical signs, which include all the variety of manifestations of a primary malignant tumor in the lung and can be supplemented by symptoms that arise in connection with the development of a second tumor in one of the internal organs. With age, the incidence of primary multiple cancers increases. This circumstance should be taken into account, since it provides some guidance for the targeted search and analysis of complaints of patients and clinical manifestations of morbidity in people of the older age group, who come to specialized clinics and hospitals for lung cancer. We observed 67 patients with primary multiple lung cancer.

The clinical manifestations of primary multiple lung cancer with a synchronously developing tumor in another organ have some pathognomonic signs. They consist of symptoms that appear both in connection with the local development of each of the independent tumors, and expressing the reaction of the whole organism of patients to the effects of products of tumor metabolism.

Over time, as the tumor in the lung grows, the local symptoms of polyneoplasia most often increase, gradually prevailing in the clinical picture of the disease and become especially pronounced in the late stages — with advanced stages of cancer. The simultaneous formation and development of the second tumor in some internal organ is also accompanied by the appearance of additional peculiar complaints and various local clinical signs characteristic of the site of the lesion. With synchronous polyneoplasia, depending on the organ, which, along with the lung, has become the site of development of the second tumor, the clinical manifestations and complaints of patients change at different periods of the disease. at the same time, the disorders that cause the most anxiety may obscure others, no less significant, even appearing earlier in time, but less disturbing. At the time of seeking help, they seem to fade into the background and often patients do not immediately mention them. These complaints are most often related to lung dysfunction.

Gradually, various manifestations of each of the simultaneously developing tumors become a source of the formation of independent disorders. In this case, complaints of patients may be incorrectly perceived as pathogenetically interconnected manifestations of a single blastomatous lesion in the lung and beyond. Then an incorrect interpretation of the clinical manifestations of the disease can lead to an erroneous interpretation of the true primary multiple lesion — polyneoplasia — as far-reaching lung cancer with hematogenous metastases in the internal organs. Distinguishing these diseases helps to take into account some biological features of the development of each of them. Thus, the hematogenous dissemination of primary lung cancer is characterized by a peculiar tropism of its metastases to certain anatomical structures, sometimes called “target organs”: liver, kidneys, adrenal glands, brain, skeleton bones. Meanwhile, lung cancer with polyneoplasia is most often and naturally combined with the development of a second primary tumor in other organs: the larynx, the opposite of the lung, in the stomach or intestines, in women, in the mammary gland, uterus. All these organs are extremely rarely become the site of development of hematogenous metastases of lung cancer. When studying the clinical manifestations of the disease, bearing in mind polyneoplasia, one should always take into account the probable belonging of such patients to the “risk group” in relation to the development of a tumor in addition to the lung in another organ in terms of the totality of individual symptoms. The most difficult is the clinical interpretation of complaints and other symptoms of the disease in patients with polyneoplasia with a primary tumor in the lung and lung cancer with hematogenous metastases with blastomatous lesions of the kidney, adrenal gland, pancreas, and other more rare localizations. A correct assessment of the clinical manifestations and symptoms of the disease can then be helped by taking into account the relative duration, the isolation of the locality of local manifestations in primary multiple cancer and, on the contrary, the signs of extensive dissemination with the involvement of many organs and anatomical structures during hematogenous metastasis of the tumor.