Microscopically, AAH is a well-demarcated focus of epithelial proliferation, containing cuboidal to low-columnar cells resembling club cells or type II pneumocytes. These demonstrate various degrees of cytologic atypia, including hyperchromasia, pleomorphism, prominent nucleoli. However, the atypia is not to the extent as seen in frank adenocarcinomas. Lesions of AAH are monoclonal, and they share many of the molecular aberrations (like KRAS mutations) that are associated with adenocarcinomas.Signet ring and clear cell adenocarcinoma are no longer histological subtypes, but rather cytological features that can occur in tumour cells of multiple histological subtypes, most often solid adenocarcinoma. Treatment
The treatment of adenocarcinoma of the lung depends on several factors including stage, resectability, performance status, histology and genomic alterations acquired by the individual tumor. As in most cancer types, treatment approaches can be broadly divided into 5 categories: surgery, chemotherapy, radiotherapy, targeted therapy and immunotherapy. Surgery
Early stage (I, II and IIIA) lung adenocarcinomas are typically treated surgically to remove the tumor with pneumonectomy or lobectomy, if it is found to be resectable with imaging studies and biopsies and if the patient is considered able to tolerate surgery. Video-assisted thorascopic surgery (VATS) is often adopted, which consists in the insertion of a thorascope inside a small incision made in the chest; a lobe can be removed via the scope through this small incision. Chemotherapy
For advanced (stage IV) and unresectable lung tumors, the first-line therapy is platinum-based doublet chemotherapy, combining cisplatin or carboplatin with another cytotoxic agent.
Atelectasis is the collapse or closure of a lung resulting in reduced or absent gas exchange. It is usually unilateral, affecting part or all of one lung. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often called a collapsed lung, although that term may also refer to pneumothorax.It is a very common finding in chest X-rays and other radiological studies, and may be caused by normal exhalation or by various medical conditions. Although frequently described as a collapse of lung tissue, atelectasis is not synonymous with a pneumothorax, which is a more specific condition that can cause atelectasis. Acute atelectasis may occur as a post-operative complication or as a result of surfactant deficiency. In premature babies, this leads to infant respiratory distress syndrome. The term uses combining forms of atel- + ectasis, from Greek: ἀτελής, "incomplete" + ἔκτασις, "extension". Signs and symptoms
May have no signs and symptoms or they may include:
cough, but not prominent;
chest pain (not common);
breathing difficulty (fast and shallow);
low oxygen saturation;
pleural effusion (transudate type);
cyanosis (late sign);
increased heart rate.It is a common misconception and pure speculation that atelectasis causes fever. A study of 100 post-op patients followed with serial chest X-rays and temperature measurements showed that the incidence of fever decreased as the incidence of atelectasis increased.