INTRODUCTION: Spontaneous regression of pituitary adenomas is a rare occurrence that is thought to be due to pituitary apoplexy. We would like to review the demograhic data, imaging findings, and neurologic, endocrinologic, and radiologic outcomes of patients who exhibited this unusual phenomenon. METHODS: We present a case of non-functioning pituitary adenoma (NFPA) in a 66-year-old man that underwent spontaneous regression. We also performed a systematic literature review on cases of pituitary adenomas that exhibited spontaneous regression, in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: There have been only 27 reported cases of spontaneous regression observed in all pituitary adenomas, 16 of which are NFPAs. Headache was the most common symptom while decreased visual acuity and oculomotor nerve palsy were the most common sign. Pituitary hemorrhage was seen in two-thirds of cases, while findings suggestive of pituitary infarct, such as enhancement of the sphenoid sinus mucosa. were seen in one-third. Complete radiographic remission was observed in 62% of cases, with an 11% recurrence rate seen at least two years after the initial imaging. Neurologic recovery was reported in 88% and endocrinologic recovery from hypopituitarism was 40%. CONCLUSION Most patients exhibited neurologic and endocrinologic improvement concomitant with the regression of the pituitary adenoma. However, these tumors may recur; thus, regular and long- term neuro-ophthalmologic and radiologic follow-up is advised.
Pituitary adenoma ; spontaneous regression

Although gastric hyperplastic polyps are recognized as benign lesions, there is concern regarding carcinomatous changes in the polyps, depending on their size. If the polyp size is larger than 1.0~2.0 cm, endoscopic resection is usually recommended. Gastric hyperplastic polyps easily undergo changes in their shape and size over time. However, spontaneous regression of hyperplastic polyps is very rare. We present a recent case wherein gastric hyperplastic polyps disappeared spontaneously. We present the case along with a literature review.
Neoplasm Regression, Spontaneous ; Polyps* ; Stomach

A 44-year-old male was followed-up with esophagogastroduodenoscopy due to an esophageal submucosal tumor. On the lesser curvature of the gastric low body, a 0.5 cm sized round elevated lesion with hyperemia was noticed. Two pieces of biopsy were taken from this lesion for histopathologic examination. Histology showed Langerhans cell infiltration. Immunohistochemical staining was positive for CD1a antigen, which confirmed the diagnosis of Langerhans cell histiocytosis. There was no evidence of other organ involvement. The lesions spontaneously disappeared 4 months later without any treatment. We report a very rare case of gastric Langerhans cell histiocytosis.
Adult ; Biopsy ; Diagnosis ; Endoscopy, Digestive System ; Histiocytosis, Langerhans-Cell* ; Humans ; Hyperemia ; Male ; Neoplasm Regression, Spontaneous ; Stomach

Distortion product otoacoustic emission (DPOAE) signal can be used for diagnosis of hearing loss so that it has an important clinical value. Continuously using sweeping primaries to measure DPOAE provides an efficient tool to record DPOAE data rapidly when DPOAE is measured in a large frequency range. In this paper, locally weighted least squares estimation (LWLSE) of 2f1-f2 DPOAE is presented based on least-squares-fit (LSF) algorithm, in which DPOAE is evoked by continuously sweeping tones. In our study, we used a weighted error function as the loss function and the weighting matrixes in the local sense to obtain a smaller estimated variance. Firstly, ordinary least squares estimation of the DPOAE parameters was obtained. Then the error vectors were grouped and the different local weighting matrixes were calculated in each group. And finally, the parameters of the DPOAE signal were estimated based on least squares estimation principle using the local weighting matrixes. The simulation results showed that the estimate variance and fluctuation errors were reduced, so the method estimates DPOAE and stimuli more accurately and stably, which facilitates extraction of clearer DPOAE fine structure.
Algorithms ; Hearing Loss ; diagnosis ; Humans ; Least-Squares Analysis ; Otoacoustic Emissions, Spontaneous ; Regression Analysis

Spontaneous regression of hepatocellular carcinoma (HCC) is extremely rare, and dozens of cases have been reported in the literature. In this report, we present a case of pathologically confirmed HCC that partially regressed without medical intervention. A 54-year-old Korean male with chronic hepatitis B had a hepatic mass detected by abdominal ultrasonography during a routine visit. A clinical diagnosis of HCC was made after measuring serum alpha-fetoprotein levels followed by dynamic computed tomography and magnetic resonance imaging. The patient delayed surgical resection; however, after 5 months, the size of the HCC decreased from 3.2 to 1.0 cm in diameter without any treatment. At that time the mass was surgically resected. Histopathology confirmed that the hepatic mass was consistent with partially regressed HCC and showed more intra- and peri-tumoral lymphocytes consisting of greater CD4+ T cell infiltration than what is normally seen in resected HCC.
alpha-Fetoproteins ; Carcinoma, Hepatocellular* ; Diagnosis ; Hepatitis B, Chronic ; Humans ; Lymphocytes ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neoplasm Regression, Spontaneous ; Ultrasonography

Spontaneous regression of hepatocellular carcinoma (HCC) is extremely rare, and dozens of cases have been reported in the literature. In this report, we present a case of pathologically confirmed HCC that partially regressed without medical intervention. A 54-year-old Korean male with chronic hepatitis B had a hepatic mass detected by abdominal ultrasonography during a routine visit. A clinical diagnosis of HCC was made after measuring serum alpha-fetoprotein levels followed by dynamic computed tomography and magnetic resonance imaging. The patient delayed surgical resection; however, after 5 months, the size of the HCC decreased from 3.2 to 1.0 cm in diameter without any treatment. At that time the mass was surgically resected. Histopathology confirmed that the hepatic mass was consistent with partially regressed HCC and showed more intra- and peri-tumoral lymphocytes consisting of greater CD4+ T cell infiltration than what is normally seen in resected HCC.
alpha-Fetoproteins ; Carcinoma, Hepatocellular* ; Diagnosis ; Hepatitis B, Chronic ; Humans ; Lymphocytes ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neoplasm Regression, Spontaneous ; Ultrasonography

Spontaneous regression (SR) of malignancy is a rare phenomenon, especially in patients with gastric cancer. A 77-year-old male, who was already diagnosed with gastric adenocarcinoma by endoscopic biopsy from a private clinic, was referred to our hospital. Despite our strong recommendation, the patient refused surgical therapy. A follow-up endoscopy was performed 3 months later, which revealed that the ulcer had changed into a white scar. Endoscopic biopsy revealed only chronic inflammation. Two and 6 years later, cancer recurred, and SR was confirmed both times, histologically, at the gastric body. The patient is still alive without any gastrointestinal symptoms after 13 years of follow-up. The cause of SR is yet uncertain and there are only a few suggestions of scientific mechanisms. We, herein, report this very rare case of repeated recurrence and SR of gastric cancer without clear cause.
Adenocarcinoma ; Aged ; Biopsy ; Cicatrix ; Endoscopy ; Follow-Up Studies ; Humans ; Inflammation ; Male ; Neoplasm Regression, Spontaneous ; Recurrence ; Stomach Neoplasms ; Ulcer

Spontaneous regression of metastases or primary lesions of malignancy is a most intriguing phenomenon. However there were no reports of spontaneous regression of primary renal cell carcinoma. We reviewed a case of renal mass which was considered to be a spontaneously regressed renal cell carinoma. This diagnosis was supported by the size of the renal mass, its total necrosis, and the discovery of a few remaining tumor cells. We cautiously report this case as a spontaneously regressed primary renal cell carcinoma in a 54 year old woman.
Carcinoma, Renal Cell/pathology* ; Female ; Human ; Kidney/pathology ; Kidney Neoplasms/pathology* ; Middle Age ; Necrosis ; Neoplasm Regression, Spontaneous*

Treatment of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) is difficult because the mortality rate after surgery or chemotherapy is high for these patients. Spontaneous regression of cancer is rare, especially in lung cancer. A 62-year-old man, previously diagnosed with IPF, presented with stage IIIC (T2N3M0) non-small cell lung cancer. About 4 months later, spontaneous regression of the primary tumor was observed without treatment. To the best of our knowledge, this is the first report of spontaneous regression of lung cancer in a patient with IPF.
Carcinoma, Non-Small-Cell Lung* ; Drug Therapy ; Fibrosis ; Humans ; Idiopathic Pulmonary Fibrosis* ; Lung Neoplasms ; Middle Aged ; Mortality ; Neoplasm Regression, Spontaneous

Animals ; Antigens, Neoplasm ; immunology ; Apoptosis ; Cell Differentiation ; Humans ; Macrophages ; pathology ; Neoplasm Regression, Spontaneous ; immunology ; pathology ; physiopathology ; Neoplasms ; immunology ; pathology