The approach of scratch-imprint cytology: Is it an alternative to frozen section for intraoperative assessment of pulmonary lesions?

To address the diagnostic performance of scratch-imprint cytology (SIC), in this study we compared intraoperative diagnoses of pulmonary lesions between SIC and frozen section histology (FSH) for accuracy with respect to the final pathological diagnosis. We histologically divided 206 pulmonary lesions (resected surgically) into two groups (benign and malignant) and compared each intraoperative diagnosis by SIC and FSH with the final pathological diagnoses. We also examined the radiological existence of pure ground-glass opacity (GGO) nodules in each group. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 91.5%, 100%, 100%, 63.6%, and 92.6%, respectively for SIC, and 98.2%, 100%, 100%, 92.1% and 98.5%, respectively, for FSH. Thus, we concluded that diagnosis by SIC is reliable for malignancy, but not for benign lesions. All pure GGO nodules (19; 9.2%) were noninfectious and malignant with a high accuracy of FSH diagnosis (100%), in comparison with those of low accuracy with a SIC diagnosis (57.9%). SIC can be an appropriate intraoperative diagnostic tool where multiple cytotechnologists observe intraoperative SIC preparations scratched evenly across the whole lesion including the peripheral area of the mass.

Analysis of key clinical features for achieving complete remission in stage III and IV non-small cell lung cancer patients.

BACKGROUND: Although development of immune checkpoint inhibitors and various molecular target agents has extended overall survival time (OS) in advanced non-small cell lung cancer (NSCLC), a complete cure remains rare. We aimed to identify features and treatment modalities of complete remission (CR) cases in stages III and IV NSCLC by analyzing long-term survivors whose OS exceeded 3 years. METHODS: From our hospital database, 1,699 patients, registered as lung cancer between 1st Mar 2004 and 30th Apr 2011, were retrospectively examined. Stage III or IV histologically or cytologically confirmed NSCLC patients with chemotherapy initiated during this period were enrolled. A Cox proportion hazards regression model was used. Data collection was closed on 13th Feb 2017. RESULTS: There were 164 stage III and 279 stage IV patients, including 37 (22.6%) and 51 (18.3%) long-term survivors and 12 (7.3%) and 5 (1.8%) CR patients, respectively. The long-term survivors were divided into three groups: 3 ≤ OS < 5 years, 5 years ≤ OS with tumor, and 5 years ≤ OS without tumor (CR). The median OS of these groups were 1,405, 2,238, and 2,876 days in stage III and 1,368, 2,503, and 2,643 days in stage IV, respectively. The mean chemotherapy cycle numbers were 16, 20, and 10 in stage III and 24, 25, and 5 in stage IV, respectively. In the stage III CR group, all patients received chemoradiation, all oligometastases were controlled by radiation, and none had brain metastases. Compared with non-CR patients, the stage IV CR patients had smaller primary tumors and fewer metastases, which were independent prognostic factors for OS among long-term survivors. The 80% stage IV CR patients received radiation or surgery for controlling primary tumors, and the surgery rate for oligometastases was high. Pathological findings in the stage IV CR patients revealed that numerous inflammatory cells existed around and inside resected lung and brain tumors, indicating strong immune response. CONCLUSIONS: Multiple line chemotherapies with primary and oligometastatic controls by surgery and/or radiation might achieve cure in certain advanced NSCLC. Cure strategies must be changed according to stage III or IV. This study was retrospectively registered on 16th Jun 2019 in UMIN Clinical Trials Registry (number UMIN000037078).

A biosafety algorithm for the protection of pathology staff during intraoperative examinations of pulmonary lesions.

We aimed to propose a biosafety algorithm for the protection of pathology staff during intraoperative examinations of pulmonary lesions when working with cytological imprints and/or frozen sections for the intraoperative diagnosis of pulmonary lesions. We examined 148 pulmonary surgical tissues obtained intraoperatively for imprint cytology (IC) and for frozen sectioning and compared the diagnoses against the final pathological diagnoses. We analyzed concordance and non-concordance rates and then used the data to produce a biosafety algorithm. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of scratch-IC were 91%, 100%, 100%, 50% and 92%, respectively, and those of frozen sectioning were 99%, 100%, 100%, 96% and 99%, respectively. Our data indicate that frozen sectioning is unnecessary if scratch-IC yields a 'malignant' diagnosis but recommended with a 'benign' diagnosis. When a scratch-IC preparation deemed inadequate for a diagnosis or an abscess, the pathologist must consult the surgeon concerning the possibility of granuloma with caseous necrosis and should ask the surgeon to be prepared for a frozen section. If granuloma with caseous necrosis is found in the frozen section, the pathologist must immediately communicate the information to entire staff and perform a PCR test before making a permanent section.

Diagnostic utility and pitfalls of intraoperative pulmonary imprint cytology based on final pathological diagnoses.

OBJECTIVE: This study aimed to determine the reliability of imprint cytology (IC) for intraoperative diagnosis of pulmonary lesions. METHODS: We reviewed 113 cases of pulmonary lesion resection for which a scratch imprint was made intraoperatively. We divided the specimens into two groups (benign and malignant) and compared the scratch IC-based diagnoses against the final histopathological diagnoses in each group for concordance. We also analysed those cases in which the scratch IC preparation was classified as inadequate. RESULTS: The sensitivity, specificity, positive and negative predictive values, and accuracy of IC diagnoses among the patient cohort were 87.7% (72/82), 100% (7/7), 100% (72/72), 41.2% (7/17) and 88.8% (79/89), respectively. IC yielded some false-negative results in terms of malignancy, although most of these imprints were of early cancer or cancer with mild cytological atypia. Five (41.6%) of 12 lesions for which the imprint was deemed inadequate were diagnosed histologically as granulomas with caseous necrosis. CONCLUSION: IC-based diagnoses of pulmonary lesions as malignant corresponded well with the final histopathological diagnoses, but IC-based diagnoses of negative (ie, without malignant cells) were not as reliable. Thus, pathologists should recognise the limitations of IC, especially for identifying malignant lesions. Also, the possibility of latent bacterial infection in a granuloma with caseous necrosis indicates that an IC preparation deemed inadequate for diagnosis should not be ignored.

Liposome-encapsulated hemoglobin accelerates bronchial healing after pneumonectomy in the rat with or without preoperative radiotherapy.

Liposome-encapsulated hemoglobin (LEH) has been reported to accelerate wound healing in the stomach and skin in an experimental setting. LEH was tested in bronchial anastomotic healing after radiation and pneumonectomy in the rat. Sprague-Dawley rats (n = 61) received preoperative radiation (20 Gy) to the chest and underwent left pneumonectomy with bronchial stump closure using the Sweet method 4 days later, when they were randomized to receive intravenous infusion of LEH with high O2 affinity (P50 O2 = 17 mm Hg, 10 mL/kg, n = 32) or saline (n = 29). Additional rats (n = 18) were treated in the same way without preoperative radiation. Bronchial anastomotic healing was evaluated 2 days after surgery by determining the bursting pressure and infiltration of neutrophils, monocytes, and macrophages. Bronchial bursting pressure was elevated in the rats receiving LEH both in the unirradiated group (LEH 212 ± 78 vs. saline 135 ± 63 mm Hg, P < 0.05) and in rats with preoperative radiation (LEH 162 ± 48 vs. saline 116 ± 56 mm Hg, P < 0.01). Moreover, the percentage of rats with bursting pressure <100 mm Hg tended to be smaller in the unirradiated group (LEH 1/9 [11.1%] vs. saline 4/9 [44.4%], NS) and was significantly reduced in irradiated animals (LEH 3/32 [9.4%] vs. saline 11/29 [38%], P < 0.05). There were no morphological differences except for macrophage infiltration to the anastomotic area, which was significantly prominent in the LEH-treated rats (P < 0.05) regardless of the presence or absence of preoperative irradiation (IR). The results suggest that LEH with high O2 affinity may improve mechanical strength and morphological findings in bronchial anastomosis in rats regardless of the presence or absence of preoperative IR. The irradiated rats later treated with LEH had equivalent or better bronchial healing than that of saline-treated naïve animals undergoing pneumonectomy alone.

[Thoracoscopic lobectomy as minimally invasive surgery].

There has always been a conflict between the proposition that surgical methods for treating lung cancer should completely remove the lesion and the seemingly contradictory proposition that they should be as minimally invasive as possible. The achievement of radicality has been pursued by specializing, and began in 1933 when Graham performed total pneumonectomy for lung cancer. In 1960, the current surgical "gold standard" for lung cancer was reached when anatomical lobectomy and lymph node dissection were performed by Cahan, and subsequently called "radical lobectomy." The pursuit of less invasiveness began in the early 1980s, after the achievement of radicality, and thoracoscopic lobectomy has been developed as a major advance. Thoracoscopic lobectomy differs only in the method of accessing the pleural cavity: the surgical procedure within the pleural cavity does not differ from the procedure for radical lobectomy. In addition, the outcome of patients who have undergone thoracoscopic lobectomy as a form of minimally invasive surgery has been reported to be better than that after open lobectomy, and it is now clear that thoracoscopic lobectomy contributes to improving patients' postoperative quality of life. Accumulating additional cases and further study will be necessary in the future.

Refractory Pneumothorax Due to Cystic Pulmonary Metastasis of a Lowgrade Endometrial Stromal Sarcoma: A Case Report.

Low-grade endometrial stromal sarcoma (LG-ESS) is a rare uterine neoplasm. Computed tomography (CT) revealed the presence of multiple small bilateral pulmonary nodules in a 58-year-old woman 1 year after surgery for LG-ESS; the clinical diagnosis was pulmonary metastasis. Hormone therapy with progesterone was initiated, after which most of the solid nodules disappeared and some transformed into cystic lesions. Seven years after hormone therapy, the patient experienced repeated pneumothorax. The cause of the pneumothorax was perforation of a metastatic focus within the wall of a small subpleural cyst that was not evident on CT images.

Significance of ZO-1, an Intercellular Adhesion Molecule, as a Prognostic Marker in Lung Adenocarcinoma.

In epithelial tissues, intercellular adhesion structures are formed between adjacent cells via intercellular adhesion factors, such as zonula occludens (ZO-1), to maintain the structure and function of tissues and organs, thereby contributing to homeostasis. Epithelial cells are polarized into apical and basal regions by tight junctions (TJs), a type of intercellular adhesion structure, and thus, their intracellular organelles are asymmetrically distributed. Normal epithelial cells maintain their cellular function by controlling cytoskeletal reorganization, motility, and division by maintaining asymmetry in their intracellular organelles. Among the features common to many cancer tissues are abnormalities in cell polarity and intercellular adhesion. Lung adenocarcinoma consists of a mixture of five different histologic types that can be distinguished in the same section: lepidic, papillary, acinar, micropapillary, and solid patterns. Therefore, it is often difficult to accurately assess histological images because the staining differs according to the histological types. In the present study, we evaluated ZO-1 staining based on histological features observed in a single section and examined its relationship to clinicopathological features. In non-tumor areas, ZO-1 was expressed on the plasma membrane and in the cytoplasm of normal alveolar epithelial cells. However, in tumor areas, ZO-1 staining was mainly localized in the cytoplasm and on the plasma membrane only in a few cells. ZO-1-negative cases tended to have poorer prognoses in all histological types, with a poorer prognosis in the solid pattern. These results suggest that ZO-1 expression in solid-pattern lung adenocarcinoma may be a useful prognostic marker.

Using hemoglobin vesicles to treat operative hemorrhagic shock after pneu- monectomy in dog models: an experimental study.

Hemoglobin vesicles (HbVs), considered as red blood cell substitutes, are liposomes encapsulating purified hemoglobin, with a phospholipid bilayer membrane (diameter: 250 nm; P50, 28 Torr). In this study, we aimed to investigate HbV function during hemorrhagic shock in lung resection and analyze the details of oxygen delivery. Left pneumonectomy was performed in dogs under mechanical ventilation, followed by rapid exsanguination of approximately 30% of the total circulating blood volume, which led to shock, reducing the mean arterial pressure (MAP) by approximately 60% of baseline. Subsequently, either 5% human serum albumin (HSA) or HbVs suspended in 5% HSA were infused for resuscitation. The MAP only recovered to 75% of baseline after HSA administration, but fully recovered (100%) after HbV administration, with significant differences between the groups (P < 0.005). Oxygen delivery was restored in the HbV group and was significantly higher than that in the HSA group (P < 0.0001). The infusion of HbVs dispersed in a 5% HSA solution compensated for the rapid loss of approximately 30% of the total circulating blood volume in a dog pneumonectomy model, even with impaired lung function. Thus, HbVs can be used for resuscitation from hemorrhagic shock during thoracic surgery.

Minimally invasive surgery for anterior flail chest injury in the acute phase: series of 10 cases.

OBJECTIVE: Anterior flail chest frequency represents a significant case of ventilator insufficiency. Surgical stabilization of acute phase of trauma is considered to effectively shorten the period of ventilation compared to conservative treatment using mechanical ventilation. We have applied minimally invasive surgery to stabilize the injured chest wall. METHODS: Surgical stabilization of predominantly anterior flail chest segments was performed using one or two bars as per the Nuss procedure, during the acute phase of chest trauma. Data from all patients were examined. RESULTS: Ten patients received surgical stabilization using the Nuss method between 1999 and 2021. All patients had already been mechanically ventilated prior to surgery. The mean period from trauma to surgery was 4.2 days (range, 1-8 days). The number of bars used was one for 7 patients, and two for 3 patients. The mean operation time was 60 min (range, 25-107 min). All patients were extubated from artificial respiration without surgical complications or mortality. Mean total ventilation period was 6.5 days (range, 2-15 days). All bars were removed in a subsequent surgery. No collapses or fracture recurrences were observed. CONCLUSION: This method is simple and effective for fixed anterior dominant frail segment.

Poly(2-ethyl-2-oxazoline)-Conjugated Hemoglobins as a Red Blood Cell Substitute.

Hemoglobin wrapped covalently with poly(2-ethyl-2-oxazoline)s (POx-Hb) is characterized physicochemically and physiologically as an artificial O2 carrier for use as a red blood cell (RBC) substitute. The POx-Hb is generated by linkage of porcine Hb surface-lysines to a sulfhydryl terminus of the POx derivative, with the average binding number of the polymers ascertained as 6. The POx-Hb shows moderately higher colloid osmotic activity and O2 affinity than the naked Hb. Human adult HbA conjugated with POx also possesses equivalent features and O2 binding properties. The POx-Hb solution exhibits good hemocompatibility, with no influence on the functions of platelets, granulocytes, and monocytes. Its circulation half-life in rats is 14 times longer than that of naked Hb. Hemorrhagic shock in rats is relieved sufficiently by infusion of the POx-Hb solution, as revealed by improvements of circulatory parameters. Serum biochemistry tests and histopathological observations indicate no acute toxicity or abnormality in the related organs. All results indicate that POx-Hb represents an attractive alternative for RBCs and a useful O2 therapeutic reagent in transfusion medicine.

Polyoxazoline-conjugated porcine serum albumin as an artificial plasma expander for dogs.

Veterinary medicine has made tremendous progress for domestic dogs, which are irreplaceable family members enriching human life. Nevertheless, no adequate supply system exists for their blood products. This study examined the synthesis, structure, safety, and efficacy of poly(2-ethyl-2-oxazoline)-conjugated porcine serum albumin (POx-PSA) as an artificial plasma expander for dogs. The aqueous POx-PSA solution showed moderately high colloid osmotic pressure and good blood cell compatibility. Actually, lyophilized powder stored for 1 year can regenerate into a homogeneous solution. The circulation half-life of POx-PSA in rats was 2.1-fold longer than that of naked PSA. Rats produced neither anti-PSA IgG antibody nor anti-POx IgG antibody, which suggests excellent immunological stealth properties of POx-PSA. Complete resuscitation of hemorrhagic shock in rats was achieved soon after injection of POx-PSA solution. Serum biochemistry tests and histopathological observations indicated no abnormality in the related organs. When POx-PSA was administered to dogs intravenously, (i) no serum biochemical or hematological alteration was observed, also (ii) no overt deterioration of animal health was observed. These results indicate that POx-PSA has potential as an artificial plasma expander for dogs.

Thymic Dedifferentiated Liposarcoma Having a Leiomyosarcomatous Dedifferentiated Component.

We report an extremely rare case of 42-year-old man, d iagnosed with thymic dedifferentiated liposarcoma (DDL) having a leiomyosarcomatous dedifferentiated component. The tumor was composed of atypical spindle cells. The morphological atypia was also observed around thymic adipose tissue. Immunohistochemically, the spindle cells were positive for desmin, smooth muscle actin, MDM2 and CDK4. MDM2 and CDK4 were also positive for the thymic adipose tissue. MDM2 amplification was confirmed by fluorescence in situ hybridization. Although there are some reports of mediastinal leiomyosarcoma, DDL may be overlooked. For accurate diagnosis of mediastinal mesenchymal tumor, careful observation of thymic adipose tissue is required with immunohistochemical study.

Enteric-type thymic adenocarcinoma: a case report and literature review focusing on prognosis based on histological subtypes.

Thymic adenocarcinoma is a rare disease and enteric-type thymic adenocarcinoma is even more rarely found. We report a resected case of a non-mucinous, enteric-type thymic adenocarcinoma in a 53-year-old woman. The operation was performed by median sternotomy, and the tumor was stage II in the Masaoka classification. Six months after the operation, recurrence-free follow-up is currently underway. Knowledge of enteric-type thymic adenocarcinoma can prevent misdiagnosis of metastatic tumors. We also determined the prognosis of enteric-type thymic adenocarcinoma based on histological subtypes through our literature review.

Hemoglobin-albumin clusters as an artificial O2 carrier: Physicochemical properties and resuscitation from hemorrhagic shock in rats.

A bovine hemoglobin (HbBv) or human adult hemoglobin (HbA) wrapped covalently by human serum albumins (HSAs), hemoglobin-albumin clusters (HbBv-HSA3 and HbA-HSA3 ), are artificial O2 carriers used as a red blood cell substitute. This article describes the physicochemical properties of the HbBv-HSA3 and HbA-HSA3 solutions, and their abilities to restore the systemic condition after resuscitation from hemorrhagic shock in anesthetized rats. The HbBv-HSA3 and HbA-HSA3 , which have high colloid osmotic activity, showed equivalent solution characteristics and O2 binding parameters. Shock was induced by 50% blood withdrawal. Rats exhibited hypotension and significant metabolic acidosis. After 15 min, the rats were administered shed autologous blood (SAB), HbBv-HSA3 , HbA-HSA3 , or Ringer's lactate (RL) solution. Survival rates, circulation parameters, hematological parameters, and blood gas parameters were monitored during the hemorrhagic shock and for 6 h after administration. All rats in the SAB, HbBv-HSA3 , and HbA-HSA3 groups survived for 6 h. The HbBv-HSA3 and HbA-HSA3 groups restored mean arterial pressure after the resuscitation. No remarkable difference was observed in the time courses of blood gas parameters in any resuscitated group except for the RL group. Serum biochemical tests showed increases in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HbBv-HSA3 and HbA-HSA3 groups compared to the SAB group. Therefore, we observed other rats awakened after resuscitation with HbA-HSA3 for 7 days. The blood cell count, AST, and ALT recovered to the baseline values by 7 days. All the results implied that HbBv-HSA3 and HbA-HSA3 clusters provide restoration from hemorrhagic shock as an alternative material for SAB transfusion.

Protective effect of ebselen on bleomycin-induced lung fibrosis: analysis of the molecular mechanism of lung fibrosis mediated by oxidized diacylglycerol.

The molecular mechanisms underlying the development of pulmonary fibrosis remain unknown, and effective treatments have not yet been developed. It has been shown that oxidative stress is involved in lung fibrosis. Oxidized diacylglycerol (DAG) produced by oxidative stress is thought to play an important role in lung fibrosis. This study assessed the effect of oxidized DAG in an animal model of pulmonary fibrosis induced by aspiration of bleomycin (BLM) into the lungs. The inhibitory effect of ebselen on pulmonary fibrosis was also investigated. In lung fibrotic tissue induced by BLM, an increase in lipid peroxides and collagen accumulation was observed. Moreover, the levels of oxidized DAG, which has strong protein kinase C (PKC) activation activity, were significantly increased over time following the administration of BLM. Western blotting showed that phosphorylation of PKCα and δ isoforms was increased by BLM. Oral administration of ebselen significantly suppressed the increase in oxidized DAG induced by BLM and improved lung fibrosis. PKCα and δ phosphorylation were also significantly inhibited. The mRNA expression of α-smooth muscle actin and collagen I (marker molecules for fibrosis), as well as the production of transforming growth factor-ß and tumor necrosis factor-α(a potentially important factor in the fibrotic process), were increased by BLM and significantly decreased by ebselen. The administration of BLM may induce lipid peroxidation in lung tissue, while the oxidized DAG produced by BLM may induce overactivation of PKCα and δ, resulting in the induction of lung fibrosis.

Core-Shell Structured Hemoglobin Nanoparticles as Artificial O2 Carriers.

This paper describes the synthesis and O2 binding properties of core-shell structured hemoglobin (Hb) nanoparticles (NPs), artificial O2 carriers of five types, as designed for use as red blood cell (RBC) substitutes. Human adult Hbs were polymerized using α-succinimidyl-ω-maleimide and dithiothreitol in spheroidal shapes to create parent particles. Subsequent covalent wrapping of the sphere with human serum albumin (HSA) yielded 100 nm-diameter Hb nanoparticles (HbNPs). The HbNP showed higher O2 affinity than that of RBC, but NPs prepared under a N2 atmosphere exhibited low O2 affinity. Entirely synthetic particles comprising recombinant human adult Hb and recombinant HSA were also fabricated. Using a recombinant Hb (rHb) variant in which Leu-ß28 of the heme pocket had been replaced with Phe, we found somewhat low O2 affinity of rHb(ßL28F)NP. Particles made of stroma-free Hb (SFHb) containing natural antioxidant enzyme catalase (SFHbNP) formed a very stable O2 complex, even in aqueous H2O2 solution. The SFHbNP showed good blood compatibility and did not affect the blood cell component functionality. The circulation half-life of SFHbNP in rats was considerably longer than that of naked Hb. All results indicate these Hb-based NPs as useful alternative materials for RBC and as a useful O2 therapeutic reagent in diverse medical scenarios.

Early reperfusion with hemoglobin vesicles into tracheal subepithelial capillaries in a mouse tracheal transplant model.

Hemoglobin vesicles (HbVs), liposomes containing concentrated hemoglobin extracted from outdated human red blood cells (RBC), are artificial oxygen carriers with a small particle size. To evaluate the reperfusion of capillaries with HbVs in a tracheal transplant model and compare it with that of RBC. Isogenic mice were used as donors and recipients in a parallel trachea transplant model. Both ends of the donor trachea were anastomosed end-laterally to the recipient trachea to form in parallel. After transplantation, 0.3 mL of HbV solution (Hb concentration, 10 g/dL) was administered via the tail vein. The recipients were euthanized 1, 4, 6, and 8 h after surgery (n = 5 in each group). The tracheas were harvested, and tracheal subepithelial capillaries (SEC) reperfusion was histologically evaluated. A significant number of particles defined as HbV by electron microscopy were observed in the SEC of the grafted tracheas 4 h after the transplant surgery and HbV administration when no RBC were found in the SECs. The number increased 6 and 8 h later. Our findings suggest that HbVs, which are smaller than RBC, can reperfuse the capillaries of grafts earlier than RBCs after transplantation and contribute to the oxygenation of transplanted tissues.

Current Status of Endoscopic Surgery in Japan: The 15th National Survey of Endoscopic Surgery by the Japan Society for Endoscopic Surgery.

In Japan, the first endoscopic surgery, a laparoscopic cholecystectomy, was performed in 1990. Since then, operative procedures have been standardized, and the safety and efficacy of endoscopic surgery have been evaluated. In accordance with the social acceptance of endoscopic surgery as a less invasive type of surgery, the number of endoscopic procedures performed has increased in all surgical domains. The Japan Society for Endoscopic Surgery (JSES) has played an important role in the development of endoscopic surgery in Japan. Notably, a technical skills certification system for surgeons was established by the JSES to train instructors on how to teach safe endoscopic surgery. Furthermore, the JSES has conducted a national survey every 2 years. In 2019, 291,792 patients underwent endoscopic surgery in all surgical domains, such as abdominal, thoracic, mammary and thyroid gland, cardiovascular, obstetrics and gynecology, urologic, orthopedic, and plastic surgery. The 15th National Survey of Endoscopic Surgery conducted by the JSES demonstrated the status of laparoscopic surgery in Japan in 2018-2019.

Papillary adenoma of the lung with a peculiar raw macroscopic feature.

We report a case of papillary adenoma of the lung with a peculiar raw macroscopic feature at intraoperative consultation. A 52-year-old man was admitted to our hospital for the evaluation of a solitary peripheral nodule in the left lower lobe which was detected with chest CT. When we took staples off from the stump of the partially resected lung in order to make a frozen section diagnosis, granular fragments leaked out from the stump. On the cut surface, the dark reddish and granular tumor grew expansively; however, hemorrhage and necrosis were absent. Histologically, granular fragments were mainly composed of papillary structures, which consisted of a single layer of cuboidal to low columnar cells with round to oval nuclei lining the surface of the fibrovascular cores. Characteristically, papillary structures lacked elastic fibers in the stroma and were packed within an elastic fiber framework derived from pre-existing alveolar structures. We considered that high intratumoral pressure might have made the granular fragments leak out of the stump as soon as we removed staples and that peculiar macroscopic findings before fixation may be a diagnostic clue for papillary adenoma.