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Objective To identify factors that influence the inter-observer reproducibility of the routine, conventional Pap smear cytology (Pap smear test) in a network of certificated laboratories in a middle-income Latin American country. Methods Twenty-six laboratories provided each an average of 26 negative for malignancy ( NILM) and high-grade squamous intraepithelial lesion ( HSIL) Pap smears. An external panel reviewed the slides. The kappa index and multilevel logistic regression were used to estimate the reproducibility and odds ratios ( OR) of a false result with 95% confidence intervals (95% CI), respectively. Results are presented for laboratories that collect (collector laboratories) and do not collect (non-collector laboratories) samples. Results The agreements ranged widely (median kappa 0.51, range 0.16-0.70). The overall false-positive ( FP) and false-negative ( FN) rates were 31% (95% CI 27-35) and 11% (95% CI 7-17). Among collector laboratories ( N = 14), a bigger sample collection volume decreased the probability of a FP ( OR-adjusted 0.05, 95% CI 0.02-0.1) whereas the number of quality defects ( OR-adjusted 1.67, 95% CI 1.25-2.24), high workload ( OR-adjusted 5.52, 95% CI 3.85-7.92) and collection by cytotechnologists ( OR-adjusted 1.28, 95% CI 1.15-1.42) or health professionals ( OR-adjusted 2.26, 95% CI 2.04-2.49) instead of nursing assistants increased it. Among non-collector laboratories ( N = 9), the FP rate increased with the number of quality defects ( OR-adjusted 1.86, 95% CI 1.06-3.26) but decreased if the samples were collected by health professionals instead of nursing assistants ( OR-adjusted 0.37, 95% CI 0.17-0.80). No significant associations were observed for FN. Conclusions Staff in charge of cervical sampling significantly determined the reproducibility of the Pap smear test, but this depended on whether the laboratory collects samples or read samples collected elsewhere. [ABSTRACT FROM AUTHOR]

, , 463-471. (). A qualitative and quantitative histological study was made of the pulmonary trunk and muscular pulmonary arteries of a male and a pregnant female llama born and living at an altitude of 4,720 m above sea-level in the Peruvian Andes. A similar study was made on the fetal llama. The individual cardiac chambers of the two adults were weighed. Our results show that in the adult llama there is no hypertrophy of the right ventricle or of the media of the pulmonary trunk or small pulmonary arteries. This appears to be of evolutionary significance in respect of survival at high altitude and suggests that the llama does not have a sustained significant pulmonary hypertension. The pulmonary arteries of the fetal llama are thick-walled and we associate this with the physiological pulmonary hypertension of fetal life. [ABSTRACT FROM PUBLISHER]

, , 701-708. Pathological data on chronic mountain sickness are scarce due to the fact that the disease is ameliorated or cured by descent to a low altitude. In this report we describe a case of chronic mountain sickness occurring in a woman of 48 years at Cerro de Pasco (4,300 m above sea level). The necropsy findings are compared with the limited pathological observations reported by others. It is apparent from our findings that in fatal cases the main changes are located within the pulmonary circulation. So far histological studies have been reported only in cases of the secondary form of chronic mountain sickness. The basic pathology of the primary form (Monge's disease) remains to be defined. [ABSTRACT FROM PUBLISHER]

The walls of the small pulmonary arteries of the llama are thinner than those of other domestic animals native to the Peruvian Andes. It is suggested that this may be of evolutionary significance in respect of survival at high altitude. [ABSTRACT FROM PUBLISHER]

Background: Replacement of cytology screening with HPV testing is recommended and essential for cervical cancer elimination. HPV testing for primary screening was implemented in 12 laboratories within 9 Latin American countries, as part of the ESTAMPA cervical cancer screening study. Our observations provide information on critical operational aspects for HPV testing implementation in diverse resource settings., Methods: We describe the implementation process of HPV testing in ESTAMPA, focusing on laboratory aspects. We assess the readiness of 12 laboratories to start HPV testing and their continuity capacity to maintain good quality HPV testing until end of recruitment or up to December 2021. Readiness was based on a checklist. Information from the study database; regular meetings and monitoring visits; and a questionnaire on laboratory operational aspects sent in May 2020 were used to assess continuity capacity . Compliance with seven basic requirements (readiness) and eight continuity requirements (continuity capacity) was scored (1 = compliant, 0 = not compliant) and totaled to classify readiness and continuity capacity as very limited, limited, moderate or high. Experiences, challenges, and enablers of the implementation process are also described., Results: Seven of 12 laboratories had high readiness , three moderate readiness , and of two laboratories new to HPV testing, one had limited readiness and the other very limited readiness . Two of seven laboratories with high readiness also showed high continuity capacity , one moderate continuity capacity , and the other four showed limited continuity capacity since they could not maintain good quality HPV testing over time. Among three laboratories with moderate readiness , one kept moderate continuity capacity and two reached high continuity capacity. The two laboratories new to HPV testing achieved high continuity capacity . Based on gained expertise, five laboratories have become part of national screening programs., Conclusion: High readiness of laboratories is an essential part of effective implementation of HPV testing. However, high readiness is insufficient to guarantee HPV testing high continuity capacity , for which a "culture of quality" should be established with regular training, robust monitoring and quality assurance systems tailored to local context. All efforts to strengthen HPV laboratories are valuable and crucial to guarantee effective implementation of HPV-based cervical screening., Competing Interests: Author MH was employed by SMS-Oncology, Amsterdam, Netherlands. Author FD was employed by Laboratorio de Patología Oncológica, SAC, Peru. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rol, Picconi, Ferrera, Sánchez, Hernández, Lineros, Peraza, Brizuela, Mendoza, Mongelós, Cabrera, Rodríguez de la Peña, Correa, Terán, Colque Reynaga, García, Ramírez, Hernández-Nevarez, Doimi, Ramón, Arias-Stella, Zúñiga, Villagra, Bobadilla, Cardinal, Valls, Lucas, Baena, Fleider, Venegas, Cruz-Valdez, Rodríguez, Calderón, Wiesner, Luciani, Broutet, Herrero and Almonte.)

Introduction: Human papillomavirus (HPV) testing is replacing cytology in primary screening. Its limited specificity demands using a second (triage) test to better identify women at high-risk of cervical disease. Cytology represents the immediate triage but its low sensitivity might hamper HPV testing sensitivity, particularly in low-income and middle-income countries (LMICs), where cytology performance has been suboptimal. The ESTAMPA (EStudio multicéntrico de TAMizaje y triaje de cáncer de cuello uterino con pruebas del virus del PApiloma humano; Spanish acronym) study will: (1) evaluate the performance of different triage techniques to detect cervical precancer and (2) inform on how to implement HPV-based screening programmes in LMIC., Methods and Analysis: Women aged 30-64 years are screened with HPV testing and Pap across 12 study centres in Latin America. Screened positives have colposcopy with biopsy and treatment of lesions. Women with no evident disease are recalled 18 months later for another HPV test; those HPV-positive undergo colposcopy with biopsy and treatment as needed. Biological specimens are collected in different visits for triage testing, which is not used for clinical management. The study outcome is histological high-grade squamous intraepithelial or worse lesions (HSIL+) under the lower anogenital squamous terminology. About 50 000 women will be screened and 500 HSIL+ cases detected (at initial and 18 months screening). Performance measures (sensitivity, specificity and predictive values) of triage techniques to detect HSIL+ will be estimated and compared with adjustment by age and study centre., Ethics and Dissemination: The study protocol has been approved by the Ethics Committee of the International Agency for Research on Cancer (IARC), of the Pan American Health Organisation (PAHO) and by those in each participating centre. A Data and Safety Monitoring Board (DSMB) has been established to monitor progress of the study, assure participant safety, advice on scientific conduct and analysis and suggest protocol improvements. Study findings will be published in peer-reviewed journals and presented at scientific meetings., Trial Registration Number: NCT01881659., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)

Erdheim-Chester disease (ECD) is a rare, xanthogranulomatous, non-Langerhans cell histiocytosis with frequent systemic involvement. Although the diagnosis is based on characteristic histological and radiological findings, its identification can be challenging because of its heterogeneous presentation. Osteosclerosis of long bones, often associated with bone pain, is the most common initial manifestation, followed by extraskeletal manifestations in approximately 50% of cases. There is no standard treatment for ECD, although recommendations have been made on the basis of small studies. A systematic approach to the diagnosis of ECD is important, because its manifestations may be life-threatening and may require specific management. We report an atypical presentation of ECD, with early cardiac, renal, and central nervous system involvement, and only late skeletal manifestations., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Molecular tests allow the detection of high-risk human papillomavirus in cervical samples, playing an important role in the prevention of cervical cancer., Objectives: We performed a study to determine the prevalence of HPV 16, HPV 18 and other high-risk human papillomavirus (pool 12 genotypes) in Peruvian females from diverse urban areas using the cobas 4800 HPV test., Methods: Routine cervical samples collected in our laboratory were analyzed by cobas 4800 HPV test., Results: A total of 2247 samples from female patients aged 17-79 years were tested. high-risk human papillomavirus was positive in 775 (34.49%) samples. Of these, 641 (82.71%) were single infections and 134 (17.29%) were multiple infections. The positivity rates for HPV 16, HPV 18, and other high-risk human papillomavirus were 10.77%, 2.0%, and 28.08%, respectively. In multiple high-risk human papillomavirus infections, the concomitance of HPV 16 and other high-risk human papillomavirus was more prevalent (13.42%)., Conclusion: Our study showed high prevalence of high-risk human papillomavirus in urban Peru, mainly among young women. In both single and multiple infections other high-risk human papillomavirus were more prevalent than HPV 16 and HPV 18, which might influence vaccine impact in our country. Furthermore, the cobas 4800 HPV test may be considered a useful tool for HPV molecular diagnosis., (Copyright © 2014 Elsevier Editora Ltda. All rights reserved.)

Mucinous mammary carcinoma (MC) is a tumor type with relatively favorable prognosis. Unlike the circumstances surrounding conventional invasive duct carcinoma, data are limited regarding precursor lesions for MC. This study characterizes patterns of mucinous ductal carcinoma in situ (DCIS) as a precursor lesion for MC. All slides from 130 cases of MC encountered between 2000 and 2011 at Henry Ford Hospital, Detroit, MI were reviewed to subclassify MC, identify DCIS, and explore transition patterns from DCIS to MC. Calponin, p63, chromogranin, synaptophysin, CD56, and MIB-1 immunostaining analyses were performed in 65 cases. Among 106 cases of pure (71 type A, 35 type B) and 24 cases of mixed MC, DCIS appeared in 88 (68%) specimens, with all but 4 showing luminal mucin accumulation. Dominant patterns of mucinous DCIS were cribriform/solid (66), cribriform and papillary (7), papillary (5), micropapillary (3), and flat (3). Fifty-seven (68%) cases of mucinous DCIS demonstrated transitions from DCIS to MC. Luminal mucinous distention, focal flattening and attenuation of the epithelium, and disruption of the duct wall resulting in a mucocele-like extravasation of malignant epithelia with escaping mucin was a transition pattern seen with all architectures of DCIS and in all types of MC. This was the only pattern of transition to type A MC. The epithelial outpouching, formation of a cleft with accumulation of mucin around the epithelium, and transition into mucin pools with floating tumor cell clusters was the second transition pattern that went from cribriform/solid DCIS to type B and mixed MC. DCIS preceding aggressive phenotypes of MC (type B and mixed) more often had a cribriform/solid architecture, higher nuclear grade, and higher Ki-67-labeling index (all P<0.05). In summary, mucinous DCIS is a precursor to MC with distinctive features that link patterns of DCIS with aggressive MC phenotypes. The 2 observed transitions between mucinous DCIS and MC suggest that pathogenesis of different types of MC is different correlating with less or more aggressive behavior of the latter.

Ohashi described for the first time the IPMN on 1982 as a pancreatic neoplasia with mucine cells forming papillae and producing dilatation of the main pancreatic duct or its branches. The IPMN represent the 1% of the pancreatic tumors and 5% of the cystic neoplasias. It is potentially malignant in a period of five years being more frequent in males between 60-70 and clinically these patients' presents as acute, recurrent or chronic pancreatitis, with an incidence of malignancy from 25% to 70%. CT scan and cholangio MRI allows the diagnosis, the variety, localization and possibility of determine malignancy. The treatment is the Whipple resection. We are reporting the case of an obese middle age male, being observed along the last 10 years because of recurrent pancreatitis with a cystic lesion of the head of the pancreas. The CT scan, endoscopic-ultrasound and the analysis of the liquid content suggested a mucinous lesion, reason why the patient underwent a pancreatic-duodenal resection. The histology study confirms the diagnosis of IPMN.

The role of bioactive compounds in wound repair is critical. The preliminary work described herein includes the study of the effects of second degree burns in a Rex rabbit model and the action of human umbilical cord cells on the regulation and secretion of bioactive compounds. When applied on blood scaffolds as heterograft matrices, fibroblasts proliferate from these primary cultures and release biologically active peptides under tight control. Our work in progress indicates that mesenchymal stem cell (MSC)-mediated therapy provides better quality and more efficient burn reepithelialization of injured tissues by controlling the release of these peptides. Improvement of wound aesthetics is achieved in less time than without MSC-mediated therapy. Well-organized epidermal regeneration and overall better quality of reepithelialization, with no rejection, can be demonstrated consistently with periodic biopsies. Our studies indicate that MSCs have the capacity to produce, regulate, and deliver biologically active peptides that result in superior regeneration, compared with conventional treatments., (© 2012 New York Academy of Sciences.)

We report for the first time a case of 2.5 cm polypoid cervical endometriosis with a superficial growth pattern in a 48-year-old patient with past tubal ligation. The lesion showed metaplastic changes (clear cell, eosinophilic, micropapillary) and a prominent Arias Stella reaction in the absence of concomitant pregnancy but presumably related to phytoestrogenic treatment. The eutopic endometrium, however, had a usual proliferative appearance, implying that it showed a different response from the endometriotic tissues, suggesting the possibility of a metaplastic origin for the endocervical polypoid endometriosis. The unusual histology of the lesion led to an erroneous diagnosis of papillary serous carcinoma in the biopsy. This was subsequently excluded on finding endometrial-type stroma surrounding glands, and was confirmed immunohistochemically by a low Ki-67 index and negativity for p53.

In the last few years a variety of new forms of chronic colitis have been described with defined histological characteristics. It is important both for the gastroenterologists and pathologists to be acquainted with this new clinic pathological entities. The present article is a review of the anatomo-pathological characteristics of the different types of colitis.

Three obese patients underwent sleeve gastrectomy. They developed gastric dehiscence with generalized peritonitis, sepsis and shock, being operated as total gastrectomy of the remanent stomach with Roux in Y esophago-jejunostomy reconstruction as a last chance of life saving procedure.

Aim: To determine the prevalence of peptic ulcer and gastric adenocarcinoma in a population of middle and high socio-economic status in Lima, Peru, between 1985 and 2002., Material and Methods: The prevalence of gastroduodenal ulcer and gastric adenocarcinoma was determined after studying by esophagogastroduodenoscopy 31,446 patients at the Policlínico Peruano Japonds (PPJ) between 1985 and 2002. All patients had chronic upper gastrointestinal symptoms and had endoscopically proven diagnosis of active peptic ulcer or histological diagnosis of gastric adenocarcinoma., Results: Analysis of PPJ population identified a decrease in the prevalence of gastric ulcer and duodenal ulcer from 3.15% and 5.05% respectively in 1985, to 1.62% and 2.00% respectively in 2002. Gastric adenocarcinoma prevalence also decreased from 3.19% in 1988 to 0.92% in 2002. The prevalences of gastric ulcer (OR = 1.49, 95% IC 1.26-1.77, p < 0.001), duodenal ulcer (OR = 1.32, 95% IC 1.15-1.51, p < 0.001) and gastric adenocarcinoma (OR = 1.53, 95% IC 1.25-1.86, p < 0.001), decreased in the last eight years., Conclusions: Over the study period, there was a significant decrease in the prevalence of peptic ulcer and gastric adenocarcinoma at the Policlinico Peruano Japonés, where patients from middle and high socio economic status are attended.

Objective: To compare the prevalence of Helicobacter pylori infection in native Peruvians and Japaneses residing in Peru., Methods: Prospective study carried out at "Policlinico Peruano-Japonés" (Lima-Perú). We included Peruvians and Japaneses residing in Peru with chronic symptoms of the upper gastrointestinal tract. Both groups were from medium to high socioeconomic status. We excluded patients with peptic ulcer. PCR, rapid ureasa test and IgG ELISA were used to diagnose the infection., Results: We evaluated 168 Japaneses (mean age 54.6 +/- 12.62 years, 75% female), and 161 Peruvians (mean age of 42.12 +/- 14.48 years, 61.5% female). Using the rapid ureasa test, the prevalence of Helicobacter pylori infection in Peruvians was 47.8%, and in Japaneses 47.0% (p=0.88). Using PCR, in Peruvians was 49.7% and in Japaneses 43.5% (p=0.28)., Conclusion: Peruvians and Japaneses residing in Peru have a similar prevalence of Helicobacter pylori infection, after controlling factors such as socioeconomic status and age, suggesting that in Peru and in these ethnic groups, there is no racial predisposition to acquire the infection.

Since its first description more than four decades ago, the atypical endometrial change associated with chorionic tissue effect has been widely confirmed in the literature. However, errors and inaccuracies in text books and other publications often occur. This review clarifies some of these misconceptions and presents a summary of new data on the histologic and immunohistochemical characteristics of the change. A brief discussion of the pathogenesis and biologic significance of the alteration is included.

We anaylize in patients from high socio economic level the histologic findings of biopsies from the gastric mucosa taken endoscopically. Patients with upper gastrointestinal symptoms were examined with esophagogastroduodenoscopy. In the histologic study we considered: presence of Helicobacter pylori, mucinous damage, displasia, atrophy and intestinal metaplasia. Patients were divided in two groups: those who endoscocopically did not present gastric or duodenal active ulcer, gastric neoplasia or were not gastrectomized or vagotomized and those in which active gastric or duodenal ulcer was found. The first group was comprised of 1406 patients (647 women and 769 men). 57.33% (806) showed presence of Helicobacter pylori in the histologic study. Males presented higher prevalence of the bacteria (57.32% vs 42.68%, p=0.021873). Atrophys was found in 8.25% and was more frequent in patients with H. pylori (78.45% vs 21.55% p=0.0000026) / Intestinal metaplasla was found in 11.24% being related more with the presence of H.pylori (74.68% vs 25.32%, p=0.0000043). In the second group comprised of 232 patients: 192 males (82.7%) 82.75% showed presence of the bacteria. There was not a statistical difference by comparing sex and age vs presence of ulcer.

Compiling our observations from the last 15 years in regard to the epidemiology of Helicobacter pylori in Perú, we have analized 3005 cases. Studying and comparing the rates of infection among japanese inmigrants living in Perú for more than 10 years, niseis, japanese visitors and peruvians, we found similar rates. According to these results it seems that at least in japaneses there is not any genetic predisposition to acquire the infection. Studying peruvians of different socioeconomic levels, we observed similar rates of infection with the exception of women of high socioeconomic level. It seems that the last group of people is not exposed to the different mechanisms of infection. We found similar rates of infection in patients of low socioeconomic level living in the coast, sierra and jungle. Our studies in children showed that the infection is acquired during early childhood. Therefore in Perú we have not observed an ascending rate of infection according to age as has been described in industrialized countries. Analizing water from 48 sources we found Helicobacter pylori in 24 samples, 20 of them were taken from the municipal source of water. Water seems to be an important vehicle of infection, according to our studies, in children drinking water from different sources.

The presence of mitotic figures was investigated in 215 cases of florid atypical endometrial change associated with chorionic tissue effect. Mitoses were found in 13.4% of the cases. Mitoses were occasionally observed in 10.2% of cases, and they were multiple in single microscopic fields in 2.7%. Abnormal mitoses were noted in 3.2% of the cases. The occurrence of normal and abnormal mitoses was mainly related to the early secretory type of abnormality. These observations have biologic implications, but of more practical interest, they indicate that the presence of mitoses per se are an insufficient criteria for the diagnosis of clear-cell carcinoma, particularly in women during their reproductive period.

Encephalitis developing after prolonged antineoplastic therapy in two patients with Hodgkin's disease and in one with multiple myeloma was found at autopsy to be caused by toxoplasmosis. To better understand the pathogenesis of the brain lesions, ranging from microscopic foci to some having a diameter of 6 cm. and characterized by proliferation of the organisms at the margins of expanding necrosis, an animal model was studied. Similar lesions were produced in hamsters by inducing relapse of chronic latent toxoplasmosis through administration of cortisone, cyclophosphamide, or whole body irradiation, but toxic doses of nitrogen mustard and urethane did not precipitate relapse. Notably, relapsing toxoplasmosis generally involves the brain exclusively, suggesting a special susceptibility related to immune mechanisms. The roles of cells and of antibodies in immune surveillance against this chronic infection in otherwise normal hosts are considered. In man the suppression of cellular immunities by certain antineoplastic agents would seem to be decisive in causing relapse of toxoplasmosis, rather than the replacement of immunologically active cells by neoplasm. Because the infection can be controlled with sulfadiazine and pyrimethamine, a high index of suspicion is essential to detect incipient cerebral toxoplasmosis. serial serologic testing is helpful by demonstrating titer elevations; however, poor antibody production or transferred antibody may be misleading clinically when single tests are evaluated. Similarly, a poor inflammatory cell response can make it difficult for the histopathologist to detect small lesions in these patients.

The area occupied by parenchymal cells, in sections comprising the entire half of the surface of the carotid body, is significantly greater in people born and living at 14,350 feet than in those at sea level. The enlargement and increase in weight of the carotid bodies observed at high altitudes can thus be attributed to hyperplasia of parenchymal tissue. The proliferated cells have the morphology of type I chief cells and display marked vacuolation and depletion of yellow-green, naturally fluorescing, bioamine containing granules. Although unimportant variations in size and weight in relation to age occurred at sea level, it was found that the magnitude of the carotid body enlargement increased with age at high altitudes. The augmented carotid body size and weight in relation to age at high altitudes are associated with progressive chemoreceptor insensitivity. The physiologic and pathologic significance of these findings is discussed.

Twenty-six verruga peruana nodules were studied. The presence of Factor VIII-related antigen and Ulex europaeus lectin binding, and the ultrastructural finding of rudimentary cell junctions and pinocytotic vesicles establish the endothelial character of the proliferating cells in the verruga nodules. Whereas superficial lesions could show an angiomatoid pattern, deep-situated nodules tended to present a compact type of growth. Electron-microscopic studies have shown that Bartonella bacilliformis was found abundantly in the extracellular spaces in the florid lesions and that no organisms were present in the late, resolving subcutaneous nodules. Although no true intracellular "viable" microorganisms were noted, pseudopods of cytoplasm entrapping one or two bacteria and surrounding matrix substance were seen often. The characteristics of cytoplasmic inclusions previously described in verruga cells as "chlamydozoa" were detailed. The ultrastructure of the inclusions corresponded to endothelial phagocytic cells in which complex invaginations of the cell surface had produced a labyrinth of interconnected channels and vacuoles containing degraded bacteria, extracellular matrix components, or both. We conclude that in light microscopy the finding of Rocha-Lima's inclusions is the only definite morphologic evidence of the presence of bartonella in verruga lesions.

Hemangiopericytoma, an uncommon neoplasm derived from pericytes, occurs in many locations throughout the body. The clinical course of this tumor is variable with the most malignant lesions capable of producing metastases. This report describes 5 patients who had hemangiopericytoma of the breast. All were women between 47 and 57 yr old. The tumors varied from 3.2 to 19 cm (average, 9 cm). Three were treated by mastectomy and two by local excision. All remained disease free for a median duration of 22 mo and for an average of 46 mo (3 to 144 mo). We have found eight additional already published examples of mammary hemangiopericytoma in adult women ranging in age from 33 to 67 yr (average, 51 yr). The tumors averaged 6 cm (1 to 29 cm) in diameter. Three were treated by mastectomy and 5 by excision. All 8 patients remained disease free at last follow-up, averaging 84 mo (16 to 276 mo). Thus, it appears that hemangiopericytoma arising in the breast is a clinically low-grade form of sarcoma regardless of tumor size. Whenever possible, initial treatment should be complete local excision with breast preservation. Total mastectomy may be necessary for exceptionally large lesions.

A severe degree of hyperplasia of the chief cells occurs in bovine carotid bodies at high altitudes, compared to sea level. As a result, the carotid body from an animal at high altitudes is significantly heavier and larger than the carotid body from an animal at sea level (P less than .001). In eight of 20 (40%) animals at high altitudes, the hyperplastic reaction had progressed to form chemodectomas. The findings suggest that neoplasia can result from chronic stimulation by a biologically essential environmental factor (atmospheric PO2) that acts pharmacologically on the target tissues (chief cells of the carotid body).

We have shown that in some cases fully developed florid verruga peruana nodules, as well as late-resolving, deeply situated lesions, can histologically suggest a variety of tumors to experienced pathologists. The compact proliferation of endothelial cells characteristic of florid verruga lesions can give rise to two pseudoneoplastic histologic patterns. One consists of sheets or islands of cells arranged in an epithelioid or pseudoepithelioid pattern (cases 1 and 2) in which the following histologic diagnoses were considered: squamous carcinoma, sweat gland carcinoma, epithelioid hemangioendothelioma, epithelioid sarcoma, melanoma and metastatic carcinoma. The other pattern of the florid lesion is characterized by a predominantly spindle cell arrangement (case 3) and in it the following diagnoses were made: Kaposi's sarcoma, fibrosarcoma, melanoma and leiomyosarcoma. The dense lymphoplasmacytic and histiocytic infiltrates of the late-resolving, deeply situated nodules (case 4) suggested the following histologic conditions: malignant lymphoma, nodular Hodgkin's disease, reticuloendotheliosis, and reticulosarcomatosis. Some histologic features thought to be of value to help in the differential diagnoses are discussed. It is emphasized that only the finding of Rocha-Lima's inclusions on light-microscopic studies and/or the demonstration of bartonella organisms in the lesions by electron-microscopic studies can objectively establish a diagnosis in a given lesion. However, knowledge of the epidemiologic data and particularly the presence of other lesions in the patient make it relatively easy to rule out neoplasia.