Complete spontaneous remission of small cell lung cancer in the absence of specific treatment: A case report

Progression to Lymph Node Metastasis After Spontaneous Regression of Pulmonary Adenocarcinoma Following Biopsy

BACKGROUND/AIM

Spontaneous regression (SR) of cancer, which indicates the natural disappearance of malignant tumors, is rare. Little is known about the mechanisms underlying SR; however, immunological reactions, infections, injuries, and medications have been presumed. Among previously reported cases of SR, lung cancer cases have been extremely limited.

CASE REPORT

Here, we present a case of lymph node metastasis exacerbation after SR of a primary adenocarcinoma following a biopsy. After complete disappearance of the primary site tumor, metastatic lymph nodes in the mediastinum gradually increased in size as a single lesion. Local treatment with resection and radiotherapy was effective for this metastasis, without recurrence for >3 years.

CONCLUSION

This is an interesting case of SR of pulmonary adenocarcinoma with inconsistent features in the primary and metastatic lesions. When physicians encounter exacerbation of metastatic sites with SR of the primary site in lung cancer, local intervention may be considered as a curative treatment.

Spontaneous regression of small cell lung cancer associated with Lambert-Eaton Myasthenic Syndrome: Case report

Spontaneous regression (SR) of cancer is very rare, especially of small cell lung cancer (SCLC). Recently, an association of paraneoplastic neurological syndrome (PNS) has been reported as a cause of SR of cancer, and onconeural antibodies are a possible factor in the SR of cancer associated with PNS. We herein report the first case of SR of SCLC combined with anti-P/Q-type of voltage-gated calcium channel (VGCC) antibody-positive Lambert-Eaton myasthenic syndrome (LEMS), a subtype of PNS. This case report suggests that SCLC may be spontaneously reduced by an autoimmune response induced by VGCC antibodies associated with LEMS. Our finding may help elucidate the mechanisms that inhibit tumor growth and cause the regression of tumors.

Pathologically confirmed spontaneous regression of small cell lung cancer after computed tomography-guided percutaneous transthoracic needle biopsy followed by surgery

BACKGROUND

Spontaneous regression of malignant tumors is a rare phenomenon, especially in primary lung cancer. The underlying mechanisms remain unclear, but they may often involve immunological mechanisms.

CASE PRESENTATION

In January 2020, a 78-year-old female underwent examination during follow-up of interstitial pneumonia. Chest X-ray and computed tomography (CT) scan revealed a 1.2 × 1.2 cm nodule in the left lower lobe. Based on CT-guided percutaneous transthoracic needle biopsy (PTNB), it was diagnosed as small cell lung cancer (SCLC). Immunohistochemical staining showed that tumor cells were positive for CD56, synaptophysin, and chromogranin A. Twenty-three days after the CT-guided PTNB, repeat CT scan showed that the tumor size regressed to 0.6 × 0.6 cm. The tumor showed positive uptake in fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT. The maximum standardized uptake value of the nodule was 2.24. PET-CT and enhanced magnetic resonance imaging of the brain showed no distant or lymph node metastasis. The patient's preoperative disease was diagnosed as cT1aN0M0, stageIA1, SCLC. In March 2020, she underwent left lower lobectomy and mediastinal lymph node dissection. Pathological examination of the resected specimen showed that the small tumor cells were dense with a high nucleus to cytoplasm ratio, and the morphological diagnosis was small cell carcinoma. The resected tumor size regressed to 0.05 × 0.02 cm, and no lymph node metastasis was observed. Because it was extremely small, immunohistochemical staining could not be conducted. Active fibrosis and inflammation were present around the tumor. Finally, the patient was pathologically diagnosed as SCLC pT1miN0M0, stage IA1. The patient is alive without recurrence 23 months after surgery with no adjuvant therapy.

CONCLUSIONS

We present a rare surgical case of pathologically confirmed spontaneous regression of SCLC after CT-guided PTNB. Although spontaneous regression is extremely rare, we should recognize this phenomenon.

Complete spontaneous remission of small cell lung cancer in the absence of specific treatment: A case report

Small cell lung cancer (SCLC) is a unique tumor that has a distinct clinical behavior and dismal prognosis. If untreated, it can become aggressively malignant, and life expectancy could be limited to weeks. Spontaneous regression of lung cancer has rarely been reported, and among them SCLC is even rarer. The underlying mechanisms of spontaneous regression are poorly understood. Here, we report a case of complete spontaneous SCLC remission in an elderly patient.