Alicia Rumayor Piña

Clear cell change in a lower lip mucocele

Oral mucocele is a common reactive lesion of the oral mucosa, which microscopically exhibits mucus extravasation surrounded by a wall of granulation tissue containing abundant foamy macrophages. Unusual variants, such as superficial mucoceles, mucoceles with myxoglobulosis-like change and mucoceles with synovial metaplasia-like change have been reported. We report a 74-year-old man who presented an asymptomatic translucent swelling on the lower labial mucosa diagnosed as mucocele showing a macrophage proliferation with extensive clear cytoplasmic vacuolation and signet-ring formation. This unusual presentation expands the microscopic spectrum of the oral mucoceles and can eventually lead to differential diagnosis with primary or metastatic clear cell neoplasms. In these cases, relevant clinical information, histochemistry and especially immunohistochemistry, are helpful for arriving at an accurate diagnosis.

Primary nasal mucosal melanoma in Brazil: clinicopathologic and immunohistochemical study of 12 patients.

Primary nasal melanoma is a rare tumor of unknown etiopathogenesis that occurs in adult and elderly patients usually diagnosed at advanced stages. The aim of this study was to analyze the clinicopathologic and immunohistochemical characteristics of 12 cases of primary nasal melanomas in Brazil. Twelve cases of primary nasal melanoma were analyzed histologically and by immunohistochemistry using the antibodies S-100 protein, HMB-45, Melan-A, CD63 (NKI/C3), CD68/KP1, fatty acid synthase (FASN), and Ki-67. The mean age of the patients was 60 years, and 7 of 12 patients were men. Microscopically, 10 cases presented level III of invasion; 4 were amelanotic; and in 7, cells were epithelioid. S-100 protein and FASN were positive in all cases, whereas 9, 8, 7, and 6 cases were positive for HMB-45, Melan-A, CD63 (NKI/C3), and CD68/KP1, respectively. Ki-67 labeling index ranged from 11.45% to 28.5% of positive cells. S-100 protein is more frequently expressed in nasal melanomas than in HMB-45, Melan-A, CD63 (NKI/C3), and CD68/KP1. FASN seems to be involved in the pathogenesis of nasal melanomas, and also, it can be helpful to confirm the diagnosis.

Pigmented Ameloblastic Fibro-odontoma Clinical, Histological, and Immunohistochemical Profile

Ameloblastic fibro-odontoma (AFO) is a slow-growing, expansive, benign odontogenic tumor, composed of ameloblastic epithelium embedded in an ectomesenchymal stroma resembling dental papilla, containing hard dental tissue in variable degrees of maturation, including enamel, dentin, and sometimes cementum. AFO typically affects the posterior mandible, causing bony expansion. We report a case of pigmented AFO in a 5-year-old boy, comprising clinical and histological features illustrated by immunohistochemistry using a large panel of antibodies, polarized light microscopy and scanning electron microscopy.

Nasopharyngeal Angiofibroma: A Clinical, Histopathological and Immunohistochemical Study of 42 Cases with Emphasis on Stromal Features

Nasopharyngeal angiofibroma is a benign but aggressive tumor of unknown etiology, typically occurring in adolescent males. It is described as a rare neoplasm; however, the prevalence seems to have geographic differences. All cases referred to our head and neck clinical and pathology service were reviewed. Most of the patients presented at an advanced stage. The clinical and radiographic features are presented and discussed. Histologically, the tumor shows a highly vascular fibrous proliferation with characteristic plump, angulated and stellate cells, categorized as fibroblasts. Immunohistochemistry was performed on 42 cases to further elucidate the nature of these cells. The stromal cells expressed vimentin and factor XIIIa, the latter expressed most commonly in the giant stellate cells. Inflammation was almost exclusively present in peripheral subepithelial areas. Mast cells were abundant, even in the absence of other inflammatory cells. Lymphatics were observed principally in peripheral regions. Proliferating cells (Ki-67 reactive) were restricted to endothelial cells.

ICAM-1 expression on immune cells in chronic villitis.

INTRODUCTION ICAM-1 expression on the villous syncytiotrophoblast (ST) is believed to participate in migration of maternal cells into the inflamed villi regardless of villitis etiology. However, its expression on immune cells in chronic villitis (CV) has yet to be analyzed. ICAM-1 induces cell-cell adhesion allowing intercellular communication, T cell-mediated defense mechanism, and inflammatory response. MATERIAL AND METHODS 21 cases of CV (all without an identifiable etiologic agent) and 3 control placentas were analyzed using ICAM-1, and for immune cells CD45, CD3 and CD68. These cells were subdivided according to their location in inflamed villi: a) within the inflamed villi and b) outside forming perivillous aggregates. RESULTS Large amounts of CD45, CD3 and CD68 were found within the inflamed villi and forming perivillous aggregates attached to areas of trophoblastic loss. Inflamed villi usually showed ICAM-1+ ST. The majority of immune cells surrounding areas of trophoblastic rupture presented marked expression of ICAM-1. In contrast, a small number of immune cells within the inflamed villi exhibited ICAM-1 expression. Only some (<5%) inflamed villi without trophoblastic rupture and with ICAM-1+ ST presented adherence of immune cells. DISCUSSION In inflamed villi of chronic villitis, the level of ICAM-1 expression on immune cells depends on their location: high in number of cells in the perivillous region and low within the villi. The strongest expression of ICAM-1 on immune cells attached to areas of trophoblastic rupture suggests that the loss of trophoblast can lead to an amplification of the inflammatory response.

Epstein-Barr Virus in Nasopharyngeal Carcinoma of Guatemalan and Brazilian Patients

Background. Nasopharyngeal carcinoma (NPC) is highly associated with Epstein-Barr virus (EBV), particularly the undifferentiated nonkeratinizing subtype. Prevalence of EBV in NPC in countries such as Guatemala and Brazil has not been studied. Methods. We analyzed 19 cases of NPC, 11 from Guatemala and 8 from Brazil, for the presence of EBV by in situ hybridization and immunohistochemistry. Additionally, 19 hyperplastic adenoids from children were analyzed for EBV by in situ hybridization, 12 from Guatemala and 7 from Brazil. Results. All the NPC cases from Guatemala and 5 from Brazil were of the undifferentiated nonkeratinizing type. EBV-negative cases comprised 2 keratinizing NPC and 1 differentiated nonkeratinizing NPC. All undifferentiated nonkeratinizing NPC from both samples showed intense positivity for EBER, while LMP-1 only focally and scarcely expressed. EBER was positive in 75% and 43% of the adenoids from Guatemala and Brazil, respectively. Conclusions. All undifferentiated nonkeratinizing NPC irrespective of origin from Guatemala or Brazil were highly associated with EBV.

Human papillomavirus in tonsillar squamous cell carcinomas from Guatemala and Brazil

OBJECTIVES A subgroup of tonsillar squamous cell carcinoma (SCC) is associated with human papillomavirus (HPV). Nevertheless, the prevalence of HPV seems to be variable in different regions and ethnic groups. There are no reports of HPV in tonsillar carcinomas in Guatemala, and data from Brazil are scarce. The aim of this study is to analyze and compare HPV presence in samples of tonsillar SCC from these countries. STUDY DESIGN This study describes the histologic features, expression of p16 by immunohistochemistry (IHC), and HPV by in situ hybridization (ISH) in 13 Guatemalan and 13 Brazilian patients. RESULTS All cases of tonsillar SCC from Guatemala were positive for p16, 92% expressed HPV by ISH, and 75% corresponded to the high-risk genotype 16/18. From the Brazilian patients, only four expressed p16, and all were negative for HPV. CONCLUSIONS Cases from Guatemala, which were mostly nonkeratinizing SCC and originated from the crypt/reticular epithelium of the tonsil, had high-risk integrated HPV, whereas in Brazilian cases, which were mostly keratinizing SCC that originated from the surface epithelium, there was no association with HPV.

Lipid droplets are involved in the process of high-grade transformation of adenoid cystic carcinoma

these cases, strong expression of PD-L1 by macrophages was a striking feature (Figure 1); three spMSIH tumours among these also showed membranous PD-L1 immunostaining of the tumour cells. By contrast, considerably less macrophage infiltration was seen in the five MSS tumours with moderate or highdegree tumour budding and, notably, in each case membranous PD-L1 immunostaining was observed in at least some tumour buds (Figure 2), although with low frequencies (<1% of the tumour buds). Applying the classification of cancers outlined by Teng et al., our observations suggest ‘adaptive immune resistance’ in microsatellite-unstable and some macrophage-rich microsatellite-stable colorectal carcinomas. This contrasts with ‘immunological ignorance’ in the microsatellite-stable and macrophage-poor colorectal carcinomas that, however, are apparently capable of mounting an ‘intrinsic induction’ of PD-L1 in some tumour buds.

Nodular swelling of the tongue.

Nodular swelling of the tongue Alicia Rumayor Pina, DDS, MSc, Roman Carlos, DDS, Luciana Yamamoto Almeida, DDS, MSc, Oslei Paes de Almeida, DDS, PhD, and Jorge Esquiche Leon, DDS, PhD University of Campinas, Piracicaba, and University of Sao Paulo, Sao Paulo, Brazil; and Centro Clinico de Cabeza y Cuello/Hospital Herrera Llerandi, Guatemala City, Guatemala (Oral Surg Oral Med Oral Pathol Oral Radiol 2015;119:260-263)