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Spindle epithelial tumor with thymus‐like elements is a quite rare and enigmatic tumor of uncertain histogenesis occurring within the thyroid. The authors present an illustrative case in a young female highlighting the cytomorphology, immunohistochemistry and molecular features, and discuss the diagnostic difficulties and therapeutic uncertainties encountered. [ABSTRACT FROM AUTHOR]

This article describes the utility of TTF-1, NapsinA, Ck5 and p63 in distinguishing between adenocarcinoma and squamous cell carcinoma, using fine needle aspiration cell block material and paraffin embedded biopsy specimens in a resource limited setting. Cytology and cell-block immunohistochemistry of circulating tumour cells Some patients with metastatic carcinoma had circulating cytokeratin positive cells that were probably benign cells and similar cells were also found in healthy volunteers. A case of SCLC developing after such treatment for a NSCLC is described, diagnosed on fine needle aspiration cytology and cell-block immunocytochemistry. [Extracted from the article]

Schwannomas are benign, encapsulated nerve sheath tumors arising from Schwann cells; several histologic variants of schwannoma have been described, including the exceedingly rare glandular schwannoma (GS). The histogenesis of the glands in GS (as well as in other peripheral nerve sheath tumors with a glandular component) remains unclear; no consensus exists as to whether glands should be interpreted as metaplastic elements or entrapped reactive glands. We report a case of GS with detailed immunohistochemical analysis of the epithelial component. We believe that our findings raise further questions regarding the histogenesis of glands in GS, casting doubts on the traditional distinction between true metaplasia and glandular entrapment. Further research is warranted in this regard. [ABSTRACT FROM AUTHOR]

This is a report of an uncommon primary pigmented papillary epithelial tumor of the sella in a 38‐year‐old man, who presented with clinicoradiological features of pituitary adenoma. Histologically, the tumor showed features reminiscent of choroid plexus papilloma, that is, conspicuous papillary epithelial morphology with presence of intacytoplasmic melanin and no mitotic activity. Immunohistochemically, the tumor was positive for pancytokeratin (AE1/AE3), S‐100 protein and CD56, while it was negative for glial fibrillary acid protein, thyroid transcription factor‐1, epithelial membrane antigen, other cytokeratins and pituitary hormones. These findings were not typical of any WHO‐defined entity and is thus best regarded as a pigmented papillary epithelial tumor of sella of uncertain histogenesis. The present case is a valuable addition to the spectrum of primary pigmented papillary epithelial tumors originating at an unusual location. [ABSTRACT FROM AUTHOR]

Introduction: Among the lymphoid organs, spleen is the largest one with rich blood supply. It serves to filter the blood, shows immune response to antigens and in fetal life acts as a haematopoietic organ to produce erythrocytes and granulocytes. As of known, the human lymphoid organs shows variations, spleen lacks the definite histogenetic changes. Aim: To find out the histogenesis of spleen in different gestational ages between normal pregnancy and hypertension in pregnancy. Materials and Methods: The present observational study was carried out on 100 human aborted and stillborn foetuses, aged between 12 to 40 gestational weeks. Out of 100 fetuses, 50 belonged to normal pregnancy and 50 belonged to hypertension in pregnancy. The foetuses were obtained from the Department of Obstetrics and Gynaecology and Department of Pathology. The tissue was processed, slides prepared and stained with Haematoxylin and eosin. The slides were observed under compound microscope using 4x,10x,40x and 100x objectives and interpreted. Results: The following microscopic features were observed in the present study at different gestational ages in normal pregnancy. At 12-18 weeks, spleen was lined by thin capsule, parenchyma with blood vessels, reticular cells and haematopoietic cells seen, at 17 weeks central arteriole started appearing. At 19 weeks trabeculae were seen, venous sinuses, central arteriole surrounded by few lymphocytes, 20-weeks; red and white pulp were seen, Peri-arteriolar lymphatic sheath was seen. At 24 weeks capsule was more thick with increased trabeculae. At 24-30 weeks germinal centre was seen along with the ring fibres. At 30-36 weeks, capsule was thick, white pulp was well defined. At 37 weeks, germinal centre was well-defined. At 38-40 weeks, the fetal spleen resembled that of an adult spleen. The present study attempted studying the histogenesis of fetal spleen in hypertension in pregnancy. The microscopic features of spleen did not show differences between normal pregnancy and that in hypertension in pregnancy. The study could not establish any comparable differences in the two situations. Conclusion: The present study served to study the splenic histogenesis to some extent. The findings in individual Author variations are still existing. The study could not conclude difference in the histogenesis of spleen in normal pregnancy and hypertension in pregnancy. This study may serve the Anatomists and the Pathologists for studying the individual variations in histogenesis of spleen. [ABSTRACT FROM AUTHOR]

To elucidate the effects of Ginkgo biloba extract during pregnancy on the fetal growth in terms of weight and renal histogenesis, 28 pregnant albino rats (Wistar) were divided into four groups A, B, C and D (n=7). Ginkgo biloba was administered orally @ 3.5, 7 and 14 mg/kg/day to group A, B and C, respectively, from 8th to 20th day of gestation. Group D served as normal group. The animals were weekly weighed and observed for toxicity during pregnancy. After parturition, different morphological features of neonates were measured and euthanized to collect kidneys for length, width, weight, cortical and medullary thickness measurement. Renal sections were prepared by paraffin tissue technique followed by hematoxylin and eosin staining for histological examination. The weight gain was non-significant in dams although significant (P=0.01) weight reduction was witnessed in neonate’s weight. kidneys weight showed highly significant (P=0.01) increase in treated groups than controls in dose-dependent manner. Interstitial edema, inflammation, tubular degenerations and hemorrhages were observed in renal sections. This experimental data suggested that extensive use of Ginkgo biloba during second and third trimester of pregnancy has a negative effect on renal genesis, thus, proving its safety to mothers during pregnancy but deleterious effects on renal histogenesis. [ABSTRACT FROM AUTHOR]

In rare cases, metastatic adenocarcinomas of different origin may exhibit the features of hepatoid carcinoma (HC), a rare malignant epithelial tumor, most commonly occurring in the ovaries and stomach, as well as in the pancreas and biliary ducts. A case of a 72-year-old female patient who developed a highly aggressive, poorly differentiated pancreatic ductal adenocarcinoma with peritoneal carcinomatosis, demonstrating hepatoid differentiation upon conventional hematoxylin and eosin staining is reported in the present study. The patient presented with severe abdominal pain, and the radiological investigations performed revealed ovarian and hepatic tumor masses and peritoneal lesions, which were surgically removed. The gross examination of the peritoneum and omentum revealed multiple solid, firm, grey-white nodules, diffusely infiltrating the adipose tissue. The microscopic examination revealed a malignant epithelial proliferation, composed of polygonal cells with abundant eosinophilic cytoplasm and irregular, pleomorphic nuclei. Certain cells presented with intracytoplasmic mucus inclusions, raising suspicion of a HC with an uncertain histogenesis. Immunohistochemical staining was performed, and the tumor cells were found to be positive for cytokeratin (CK)7, CK18 and mucin 5AC, whereas negative staining for CK20, caudal-type homeobox transcription factor 2, α-fetoprotein, paired box gene 8, GATA-binding protein 3 and Wilms tumor 1 were documented. Thus, the diagnosis of metastatic pancreatic adenocarcinoma was established. The main aim of the present study was to provide further knowledge concerning poorly differentiated metastatic adenocarcinoma resembling HC, emphasizing the histopathological and immunohistochemical features of these malignant lesions and raising awareness of the diagnostic difficulties that may arise, as well as the importance of the use immunohistochemistry in differentiating carcinomas of uncertain histogenesis. [ABSTRACT FROM AUTHOR]

Subcellular fractionation by differential ultracentrifugation has allowed the study of the cell and its organelles from a morphological, physiological, and biochemical perspective. Combined with electron microscopy, and by using animals at different stages of postnatal development, these methods yielded useful results concerning the ontogeny of synaptosomes, mitochondria, and myelin and broadened the possibilities to investigate the molecular underpinnings of cerebellar histogenesis. [ABSTRACT FROM AUTHOR]

Cytodiagnosis of a rare undifferentiated neoplasm of unknown histogenesis with red needle‐shaped crystals mimicking Auer rods is presented with histological features and differential diagnosis described. [ABSTRACT FROM AUTHOR]

Background and Aims: Spleen is the largest secondary lymphatic organ. It acts as a graveyard for RBCs, is essential for immune responses, performs lymphopoiesis in adults and haemopoiesis in fetuses. The present study was conducted to assess the histogenesis of spleen in human fetuses in view of existing literature. Material and Methods: The study was carried out on 34 formalin preserved human fetuses procured from Dr Sushila Tiwari Government Hospital, Haldwani with due clearance from ethical committee. The 6 |jm sections of the spleen were stained with Haematoxylin and Eosin and observed under light microscope. Results: At 14 tol5 weeks, spleen had extensive sinusoids filled with RBCs and few lymphocytes. At 16-18 weeks, trabecular arteries were noticed more towards centre along with extensive haemopoietic cells in the venous sinusoids. By 20th week lymphocytic aggregation had started around arterioles. By 24 weeks periarteriolar lymphatic sheath was clearly observed. At term (37-40 weeks), classical primary lymphoid follicle was present but germinal centers were not observed. Conclusion: During earlier differentiation, spleen symbolizes the function of haemopoietic activities and gradually during subsequent gestation; it establishes its identity as a principle lymphoid tissue.

Purpose: Chordomas are rare malignant bone tumours occuring in the midline of axial skeleton. We aimed to assess these tumors which has been diagnosed in our center in terms of clinical and pathologic characteristics, and differantial diagnosis difficulties. Material and Methods: We retrospectively evaluated cinical and histopathologic characteristics of 10 chordoma patients diagnosed at pathology department of Baskent University Adana Teaching and Resarch Hospital between 2009 and 2014. Results: The patients were consisted of men (n=9) and women (n=1) with the age of 61.3 (38-84) years old. The localization of chordomas were the sacrococcygeal region at eight patients (80%), lumbar vertebrae at one patient ( 10%) and clivus at one patient (10%). The mean diameter was 4.68 (2.5 -7.5) cm. Histopathologically, majority of cases were and ldquo;conventional chordoma and rdquo; while one of them was and ldquo;chondroid chordoma and rdquo;. Surgical excision was performed for all patients, only one case has recieved radiotherapy, and chemotherapy was given after surgery for one patient. Local recurrence was detected in three patients and distant metastasis (lung) was found in a patient and he died in a short time. Conclusion: Because that chordomas are rare clinical bone tumours which can be treated efficiently by appropriate surgical excision, clinical and histopathological characteristics and differential diagnosis should be well known. [Cukurova Med J 2016; 41(4.000): 771-776]

Heterotopic ossification in colorectal carcinoma is extremely rare. This report presents the case of a 57-year-old male who had undergone a low anterior resection following a diagnosis of rectal carcinoma. Histological examination showed heterotopic ossification in the tumor. The patient was referred to Ibaraki Medical Center, Tokyo Medical University, with a diagnosis of rectal carcinoma by a local physician. Abdominal computed tomography revealed thickening of the rectal wall with calcified deposits, and virtual colonoscopy showed stenosis with a mass in the rectum. The patient underwent a low anterior resection and diverting ileostomy in May 2014. Histological examination of the excised tumor showed moderately differentiated adenocarcinoma and an infiltration of spindle cells with numerous foci of osteoid and ossification, with osteoblastic rimming in the stroma. Immunohistochemical analysis of these spindle cells and osteoblasts revealed negative staining for AE1/AE3, suggesting a reactive change. There was metastasis in 1 of the 12 lymph nodes, and the tumor was diagnosed as stage IIIB (T4a, N1a, M0) rectal carcinoma. The patient had an uneventful recovery and was followed up at our outpatient clinic. In conclusion, the malignant potential of heterotopic ossification in rectal carcinoma has not been determined. However, heterotopic ossification is induced by tumor progression in a microenvironment, suggesting a high tumor malignity. The patient should be carefully monitored after surgery in terms of improved patient outcome.

Merkel cell carcinoma (MCC) is a primary neuroendocrine carcinoma of the skin. This neoplasia features aggressive behavior, resulting in a 5-year overall survival rate of 40%. In 2008, Feng et al. identified Merkel cell polyomavirus (MCPyV) integration into the host genome as the main event leading to MCC oncogenesis. However, despite identification of this crucial viral oncogenic trigger, the nature of the cell in which MCC oncogenesis occurs is actually unknown. In fact, several hypotheses have been proposed. Despite the large similarity in phenotype features between MCC tumor cells and physiological Merkel cells (MCs), a specialized subpopulation of the epidermis acting as mechanoreceptor of the skin, several points argue against the hypothesis that MCC derives directly from MCs. Alternatively, MCPyV integration could occur in another cell type and induce acquisition of an MC-like phenotype. Accordingly, an epithelial as well as a fibroblastic or B-cell origin of MCC has been proposed mainly based on phenotype similarities shared by MCC and these potential ancestries. The aim of this present review is to provide a comprehensive review of the current knowledge of the histogenesis of MCC.

Myofibroma is a rare benign mesenchymal tumor of uncertain histogenesis. A six-year-old boy presented with a unilateral lower eyelid mass of six weeks' duration. MRI revealed a circumscribed mass in the inferolateral orbit with bony erosion. A systemic examination was unremarkable. Excision with histopathology revealed a partially infiltrative spindle cell tumor with bland nuclear morphology expressing smooth muscle actin and muscle-specific actin, compatible with myofibroma. Solitary myofibroma is a rare childhood orbital tumor and may clinico-radiologically closely mimic a malignancy. Histopathology and immunohistochemistry can help reach a definitive diagnosis. Systemic evaluation and close follow up are crucial in such cases. [ABSTRACT FROM AUTHOR]

Prenatal gross morphologic, morphometric and histologic developmental features of the dromedary spleen were studied. The dromedary gestation period (13 months) was categorized into four (1-4) phases and ten developing spleens per growth phase were sampled. Splenic topographical anatomy was noted before being eviscerated from each foetus. Morphologic and morphometric features of the eviscerated spleens were immediately documented and 2 - 4 mm thick samples were collected for histological analysis. The developing spleen was dark brown in colour, semilunar shaped and significantly increased (p<0.05) in size and weight across the four phases of prenatal development. The full-term dromedary spleen was observed to have unique histological features. Its capsule had an inner smooth muscle and an outer predominant connective tissue layer. The pumping of stored blood from the muscular capsule and trabeculae was proportionate to the body's requirement. The splenic venous return was characterized by blood flow from the red pulp (venous sinusoids) to the peritrabecular sinuses, subcapsular sinuses and finally to the splenic veins. The dromedary has a sinusal type of spleen and has both open and closed types of circulation. The presence of closed circulation and absence of marginal sinus could be the reason for dromedary main health problems of blood parasites; Trypanosoma evansi. It was concluded that most of the salient features of the postnatal spleen were already evident in the first growth phase and became developed by the second phase. Other growth phases were mainly characterized by increase in sizes. [ABSTRACT FROM AUTHOR]

We previously found colonic crypts with normal epithelial lining but with corrupted shapes (NECS) beneath the adenomatous tissue of conventional adenomas (CoAs). Here we assessed the distribution of proliferating cells (PCs) and explored the possible occurrence of p53‐upregulated cells in the NECS in a cohort of CoAs. Sections from 70 CoAs and from 12 normal colon segments were immunostained with the proliferation marker Ki67. In 60 of the 70 CoAs, additional sections were immunostained for the tumor suppressor p53 protein. NECS with asymmetric, haphazardly distributed single PC or PC clusters were recorded in 80% of the CoAs, with a continuous PC domain in one or both slopes of the crypts in 17%, and with haphazardly distributed single PCs in the remaining 3% of the CoAs. In the 12 normal segments (controls), the colon crypts demonstrated normal shapes with symmetric PC domains limited to the lower third portion of the crypts. In 30% of the 60 CoAs immunostained with p53 the NECS revealed haphazardly distributed p53‐upregulated cells, singly or in clusters. In sum, the apparently normal epithelium of the NECS beneath the adenomatous tissue of CoAs revealed an unprecedented relocation of the normal PC domains. This unexpected event and the occurrence of p53‐upregulated cells strongly suggest that the crypts beneath the neoplastic tissue of CoAs harbor somatic mutations. The accretion of putative mutated NECS beneath the neoplastic canopy of CoA emerges as a previously unaddressed major event, an event that might play an important role in the histogenesis of CoA in the human colon. [ABSTRACT FROM AUTHOR]

Merkel cell carcinoma (MCC) is a primary neuroendocrine carcinoma of the skin. This neoplasia features aggressive behavior, resulting in a 5-year overall survival rate of 40%. In 2008, Feng et al. identified Merkel cell polyomavirus (MCPyV) integration into the host genome as the main event leading to MCC oncogenesis. However, despite identification of this crucial viral oncogenic trigger, the nature of the cell in which MCC oncogenesis occurs is actually unknown. In fact, several hypotheses have been proposed. Despite the large similarity in phenotype features between MCC tumor cells and physiological Merkel cells (MCs), a specialized subpopulation of the epidermis acting as mechanoreceptor of the skin, several points argue against the hypothesis that MCC derives directly from MCs. Alternatively, MCPyV integration could occur in another cell type and induce acquisition of an MC-like phenotype. Accordingly, an epithelial as well as a fibroblastic or B-cell origin of MCC has been proposed mainly based on phenotype similarities shared by MCC and these potential ancestries. The aim of this present review is to provide a comprehensive review of the current knowledge of the histogenesis of MCC. [ABSTRACT FROM AUTHOR]

Numerous lymphatic anastomosing channels in the lymph nodes are the most demonstrative finding of the rare lesion termed "vascular transformation of lymph node sinuses" (VTS). The mechanism of lymphatic vessel formation in VTS has not been studied. Vessel intussusception contributes to vascular expansion, and intraluminal pillars/posts, interstitial tissue structures or larger pillars (ITSs) and folds are the hallmarks of this process in blood vessels. The aim of this work is to assess whether these hallmarks of intussusception occur in VTS lymphatic vessels, indicating intussusceptive lymphangiogenesis. For this purpose, specimens of five cases of VTS were used for serial histological sections, immunohistochemistry and immunofluorescence in confocal microscopy, which enabled us to demonstrate the 3D image that defines the pillars. The studies showed a) meshworks of lymphatic vessels, which form complex loops, resembling sinuses of lymph nodes, b) presence of intralymphatic pillars, ITSs and folds, with a cover of lymphatic endothelial cells expressing podoplanin and a varying-sized connective core (e.g. collagen), and c) increase of vessel meshwork and linear arrangement, splitting and fusion of ITSs, pillars and folds, with remodelling and segmentation. In conclusion, the development of lymphatic vessel loops, ITSs, pillars and folds with segmentation in VTS supports intussusceptive lymphangiogenesis. This mechanism of intussusception is of interest because it participates in VTS histogenesis, contributes to general knowledge of intussusceptive lymphangiogenesis, which has received less attention than intussusception in blood vessels, and provides a basis for further studies in other lymphatic conditions. [ABSTRACT FROM AUTHOR]

Background: The human foetal suprarenal gland is structurally variant from its adult counterpart. The most distinctive features of human foetal suprarenal gland and histologically unique foetal zone, was described first by Elliott and Armour in 1911. After the first trimester, the centrally located foetal zone accounts for most of the foetal adrenal mass. The outer zone of the foetal suprarenal gland is called the "definitive zone or neo cortex"; this zone likely gives rise to the adult adrenal glomerulosa. A third zone called "transitional zone", lies just between the neocortex and foetal zone and is believed to develop into the zona fasciculata. Aims and Objectives: The current study was designed to study the histogenesis of suprarenal glands at different gestational age groups. Materials and Methods: Twenty-eight formalin preserved dead embryos and foetuses of both sexes, were obtained from the Govt. Maternity Hospital & S.V.Medical College, Tirupati, Andhra Pradesh, India. Specimens were grouped according to their gestational age groups (A,B,C,D) A= 0-12 weeks, B= 13-24 weeks, C= 25-36 weeks and D= more than 36 weeks of gestation. Specimens from group A were subjected to serial section as this group consists of embryos, and other groups were sectioned coronal and subjected to routine histological processing for H&E staining. Sections were observed for cellular details under light microscopy with 10X and 40X magnifications, and the same were photographed by microphotography. Results: Based upon the gestational age groups, histogenesis of the suprarenal gland was observed and correlated with the available literature, and the detailed results, discussion will be dealt at the time of discussion. Conclusions: Histological observation of the all the specimens observed in the present study are in agreement with those reported in the literature except that they appeared earlier in the present study than that reported in the literature. Capsule of suprarenal gland appeared at 12 weeks, sympatho-chromaffin bundles appeared before 6 weeks and zonation of cortex was observed at 8 weeks in the present study when compared to the time of appearance reported in the literature as 14 weeks, after 6 weeks and after 12 weeks respectively in the literature. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to analyze the utility of immunohistochemical markers such as CD117 and smooth muscle actin (SMA) in the diagnosis of various benign and malignant salivary gland neoplasms. Materials and Methods: The study comprises 17 samples categorized into three groups: Group I consisted of 5 histopathologically normal salivary gland tissue; Group II comprised 7 cases, of which 3 cases were pleomorphic adenoma, 3 cases were myoepithelioma and 1 case was Warthin's tumor; and Group III consisted of 5 cases, of which 1 was mucoepidermoid carcinoma and 4 cases were adenoid cystic carcinoma. The selected cases were subjected to immunohistochemistry (IHC) procedure to assess the expression pattern of CD117 and SMA. Results: In SMA, 85.8% showed severe-to-moderate intense expression among the tumor cells in benign salivary gland tumor. All the 5 malignant tumors showed the expression of SMA and 3 cases demonstrated severe expression among the tumor cells. An intense expression pattern of SMA was observed in both benign and malignant neoplasms in the periphery and stromal components of the tumor. Only two cases were positive for CD117, and connective tissue components were completely negative in both malignant and benign salivary gland neoplasms. Conclusion: Alpha-SMA can be utilized as reliable IHC markers for salivary gland neoplasms due to its diagnostic importance in tumors with myoepithelial origin indicative of the histogenesis of salivary gland tumors. [ABSTRACT FROM AUTHOR]

Abstract The spatial organization of cells during tissue differentiation is a crucial process in the morphogenesis of vertebrates. This process involves the movement, separation, and connection of cells. It is essential to elucidate the molecular mechanisms involved in these processes for the understanding of animal morphogenesis. Cell-cell adhesion molecules, called cadherins, are involved in the selective adhesion of cells. In the case of birds, the expression of these molecules in various organ systems during embryonic development has been reported in Gallus gallus domesticus. In this work, we present the immunohistochemical analysis of the differential expression of E and N-cadherin binding molecules in Columba livia embryos at various stages of gonadal morphogenesis. The expression of E and N-cadherin in embryos corresponding to the stages 41, 43 and in neonates of 2, 5, 7 and 75 post-hatching days were assessed by immunohistochemistry. Results revealed the expression of N-cadherin in the plasma membrane and the perinuclear zone of germline cells in ovaries and testes. However, the expression of E-cadherin was noticed with similar immunoreactivity pattern, in Sertoli cells and in the cells of the follicular nests. The differential expression of follicular cells and Sertoli cells positive for E-cadherin and germline cell N-cadherin positive cells were evidenced in the present work at the cell-cell interaction level. Future studies will focus on determining the expression of E and N-cadherin molecules during the migration of the primordial germ cells and the colonization of the genital ridge. [ABSTRACT FROM AUTHOR]

Abstract Of all brain regions, the 6-layered neocortex has undergone the most dramatic changes in size and complexity during mammalian brain evolution. These changes, occurring in the context of a conserved set of organizational features that emerge through stereotypical developmental processes, are considered responsible for the cognitive capacities and sensory specializations represented within the mammalian clade. The modern experimental era of developmental neurobiology, spanning 6 decades, has deciphered a number of mechanisms responsible for producing the diversity of cortical neuron types, their precise connectivity and the role of gene by environment interactions. Here, experiments providing insight into the development of cortical projection neuron differentiation and connectivity are reviewed. This current perspective integrates discussion of classic studies and new findings, based on recent technical advances, to highlight an improved understanding of the neuronal complexity and precise connectivity of cortical circuitry. These descriptive advances bring new opportunities for studies related to the developmental origins of cortical circuits that will, in turn, improve the prospects of identifying pathogenic targets of neurodevelopmental disorders. [ABSTRACT FROM AUTHOR]

The development of retina in Indian buffalo (Bubalus bubalis) has not been reported previously. The aim of the present study was therefore to report the major landmarks and the time course in the development of retina. Serial histological sections of Indian buffalo embryos and foetuses were used as group1 (<20.0 cm CVRL), group2 (>20.0 but <40.0 cm CVRL) and group3 (>40.0 cm CVRL). Age estimation was made on the basis of crown vertebral‐rump length (CVRL), which ranged between 36 and 286 days (1.6–94.0 cm). The retina in Indian buffalo was developed in a similar manner to that of the other mammals with the principal differences in the time of occurrence of various layers of this nervous tunic. In 36 days (1.6 cm stage), the foetal retina was composed of pigmented layer and the layer of neuroblasts. Differentiation of layers was first observed in 47 days (4.0 cm CVRL) which became prominent in 52 days (5.1 cm stage). At 120 days (20.5 cm stage), the differentiation of inner plexiform layer and inner nuclear layer was evident. At 143 days (31.0 cm) foetal age, the faint line in neuroblastic layer was the first evidence of the future outer plexiform layer. In foetuses of group III, the retina was comprised of all 10 layers (eight cell layers and two membranes) viz. pigmented epithelium, layer of rods and cones, outer limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, layer of nerve fibres and the inner limiting membrane. [ABSTRACT FROM AUTHOR]

Polyhydroxylated derivatives of 6-keto,7-dehydrocholesterol (ecdysteroids) are common constituents of various plants. In 1965, they were accidentally discovered in the search for the insect moulting hormone. These biologically important natural compounds are neither insect hormones nor inducers of insect ecdysis. Due to their strong anabolic, vitamin D-like effects in insects, domestic animals and humans, I propose the use of the arbitrary term vitamin D1. The present paper describes the effects of vitamin D1 on the growth and regeneration of excised epidermal cells of the tobacco hornworm, Manduca sexta (Sphingidae). The periods of programmed cell death and cell proliferation (histolysis and histogenesis, respectively) exactly coincide in insects with endogenous peaks of increased concentration of vitamin D1. Epidermal cells communicate with each other, creating a mutually integrated tissue, connected by mechanical, chemical, electrical, ionic or other so far incompletely known factors. After natural cell death, or after the artificial removal of some epidermal cells, the neighbouring cells that lose communication integrity, begin to divide mitotically to replace the disconnected part. Cell divisions are arrested as soon as the integrity of the living tissue is established. During insect ontogeny, the application of juvenile hormone causes regenerating epidermal cells to repeat the previous morphogenetic programme (i.e., development of patches of larval tissue on the body of a pupa, or metathetely). Conversely, the application of vitamin D1 (20-hydroxyecdysone) caused the regenerating cells to prematurely execute a future morphogenetic programme (i.e., development of patches of pupal tissue on the body of a larva, or prothetely). Among the key features of insect regeneration, is the arrest of cell divisions when tissues resume living cell-to-cell integrity. This prevents the formation of aberrant groups of cells, or tumours. It is well established that the main physiological systems of insects (e.g., circulatory, respiratory, neuro-endocrine) are structurally and functionally similar to corresponding systems in humans. Thus the basic principles of cell regeneration and the role of vitamin D1 in insects may also be valid for humans. The common vitamins D2 (ergocalciferol) or D3 (cholecalciferol), are exclusively lipid soluble secosterols, which require activation by UV irradiation and hydroxylation in the liver. By contrast, the neglected vitamin D1 is a natural derivative of polyhydroxylated 7-dehydrocholesterol of predominantly plant origin, which is both partly a water and partly a lipid soluble vitamin. It neither requires UV irradiation, nor hydroxylation due to 6 or 7 already built-in hydroxylic groups. Like other vitamins, it enters insect or human bodies in plant food or is produced by intestinal symbionts. Vitamin D1 causes strong anabolic, vitamin D-like effects in domestic animals and in humans. I am convinced that avitaminosis associated with a deficiency of vitamin D1 in human blood may be responsible for certain hitherto incurable human diseases, especially those related to impaired nerve functions and somatic growth, aberrant cell regeneration or formation of malignant tumours. [ABSTRACT FROM AUTHOR]

The cellular origin of Merkel cell carcinoma (MCC) is controversial. We previously hypothesized that MCC originates from hair follicle stem cells or Merkel cell (MC) progenitors residing within the hair follicle bulge. Examination of three cases of combined MCC led to the unexpected discovery that numerous keratin 20 (CK20)-positive MCs within the squamous cell carcinoma (SCC) component of combined MCC appeared morphologically normal with dendritic and oval shapes. Moreover, one extremely rare case of combined SCC and MCC showed both intra-epidermal and dermal MCCs. These three cases represent the first documentation of MC hyperplasia in MCC, besides various benign follicular neoplasms associated with MC hyperplasia. Therefore, to elucidate the proliferating potential of MCs and their histogenetic relationship with MCCs, we further investigated these cases based on pathological observations. We identified numerous cells co-expressing CK20 and the proliferation marker Ki-67, identical to the morphological and immunohistochemical features of normal MCs. This finding indicated that MCs can no longer be considered as pure post-mitotic cells. Instead, they have proliferative potential under specific conditions in the diseased or wounded skin, or adjacent to various skin tumors, including MCC. Intimate co-existence of two malignant cell components composed of intradermal and intra-epidermal MCCs, with the proliferation of normal-appearing MCs in the same lesion, lends support to the hypothesis that MCs and MCC cells are derived from MC progenitors residing within the hair follicle bulge. Specifically, MCCs are derived from transformed MC progenitors with potential for dual-directional differentiation towards neuroendocrine and epithelial lineages. [ABSTRACT FROM AUTHOR]

The increase in autoimmune diseases in recent years has drawn attention back to the thymus, with new approaches to improve and/or restore immune function being investigated. As the primary lymphoid organ responsible for functional T cell development, studies on the pre-/post-natal development of this organ and T lymphocytes in human and other species are of special interest. During our screening studies we observed structures that had not been described or mentioned previously, and named them "epitheliostromal sheaths". Associated with these unique structures were also small attached lobules (possibly reflecting the maturational stages of thymic lobules), which the authors consider as markers of histogenesis and the growth of the organ during early childhood; these findings are thus presented to researchers in this field. Approximately 1000 sections prepared from infantile thymic tissues of partial biopsy specimens were immunostained and examined. Specimens were taken from ten patients (with informed consent) in the age range of 4-9 years who underwent surgery due to congenital cardiovascular anomalies but were otherwise normal. Digital images of interest were captured to describe them in detail. Determining the immunophenotype of the compartments in these newly developing lobules assisted us greatly in defining compartments and their growth order. In summary, our findings suggest a niche-based thymus growth mechanism during childhood. We presented our findings, hoping to provide additional insight to researchers aiming to restore thymus function in adulthood and improve its immunological functions. [ABSTRACT FROM AUTHOR]

Backgound: The histogenesis process of pleomorphic adenoma (PA) of salivary gland continues to remain a controversial subject. In this neoplasm, transition occurs from an epithelial or myoepithelial cell to a stromal element and is called an epithelial-mesenchymal transition (EMT) resulting in heterogeneity. The present research was aimed to study the morphological characteristics of varied components and epithelialmesenchymal transitions in PA using histopathological and immunohistochemical (IHC) analysis. Materials & methods: For this purpose 15 PAs cases were selected from the archives and from each case of PA and 5 cases of normal salivary gland, five additional sections were cut from each for immunohistochemical analysis using E- cadherin, vimentin and α-actin. The numbers of immunoreactive cells were semiquantitatively measured and also determined the intensity of the immunostaining reaction. Result: Immunohistochemically, as the cells transitioned from the lumial cells to descrete/detached cells of ductal structures, the percentage of positive cells tends to decrease for E- cadherin and increases for vimentin and actin. Additionally, neoplastic cells towards the periphery of ducalcystic structures or completely detached cells in the stroma showed intense to moderate positivity for vimentin and alpha smooth muscle actin (α-SMA). Chondroid/ hyalinized or myxoid stroma showed variable staining with these markers. Conclusion: Our study provides the evidence that epithelialmesenchymal transition process represent the basic principle of the tisuse heterogeneity in pleomorphic adenomas. [ABSTRACT FROM AUTHOR]

Background: Primary cutaneous mucinous carcinoma (PCMC) is a rare epithelial tumor with unclear histogenesis. Methods: We evaluated the immunohistochemical expression of the estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (AR) in six cases of PCMC. The immunoreactivity of adipophilin and gross cystic disease fluid protein (GCDFP)‐15 was investigated to determine the origin of the tumor. Results: The study included five males and one female aged 50 to 69 years who presented with a cutaneous mass in the face. Immunoreactivity for ER, PR, and AR was observed in all cases, and all cases were negative for adipophilin but positive for GCDFP‐15. Conclusions: This report is the first to show AR expression in PCMC. All of followed cases manifested indolent clinical course, and the prognostic significance of hormone receptors in PCMC remains unclear. The negative immunoreactivity of PCMC for adipophilin and positivity for GCDFP‐15 suggests a more likely relationship to apocrine than to sebaceous glands. [ABSTRACT FROM AUTHOR]

Xanthomatous changes can be observed in various conditions including primary xanthomatosis that is linked to an underlying hypercholesterolemia and more commonly associated with secondary xanthomatous degenerative processes in neoplasm and chronic inflammation. Meningioma with extensive xanthomatous change is exceedingly rare. The presence of cholesterol clefts within this peculiar meningioma subtype has not been described. Herein, we report an unusual case of xanthomatous meningioma in an 83‐year‐old normolipidemic woman, who presented to us with worsening lower limb weakness and global aphasia. There was increasing evidence to suggest that the presence of xanthomatous changes in long‐standing meningioma is merely a sequela of cellular degeneration rather than true metaplastic change as previously hypothesized. Hence, the diagnosis of "xanthomatous meningioma" in the metaplastic category should be revisited and considered as a distinct histological subtype. The possible histogenesis of such intriguing phenomenon is discussed with a review of the literature. [ABSTRACT FROM AUTHOR]

Solanum khasianum is a rich source of steroidal alkaloids that are important secondary metabolites with enormous pharmaceutical uses. Development of plantlets from somatic tissues, under in vitro conditions, takes place both through adventitious shoot bud differentiation or somatic embryogenesis (SE) pathway. We observed that the physical state of medium, solid or liquid, determined the regenerant differentiation patterns from root segment explants in S. khasianum. In the solidified medium, the root segments developed adventitious shoot buds whereas somatic embryos were regenerated in the liquid medium. Varying gradients from liquid to solid medium were further used to confirm the effect of solidified condition on regeneration pathway. Histological analysis of developing shoot buds and somatic embryos was also performed to confirm their development and differentiation patterns. In order to further confirm the developmental pathways, qRT-PCR analysis of the marker genes of SE and shoot regeneration was also performed. While SOMATIC EMBRYOGENESIS RECEPTOR KINASE1 (SkSERK1) expression was significantly up-regulated during the early embryogenic stage, the LATE EMBRYOGENESIS ABUNDANT (SkLEA) protein was found to be highly expressed in the mature embryos. Expression of the HISTONE DEACETYLASE (HDA6), a repressor of SE related genes, was highly decreased during embryogenesis in the liquid culture. Furthermore, expression of the ENHANCER OF SHOOT REGENERATION  (ESR) gene was comparatively increased during shoot regeneration in the culture using solid medium. Our results point out that the physical state of the medium in S. khasianum plays a decisive role in differentiation pattern which was independent of hormonal supplements. [ABSTRACT FROM AUTHOR]

Angiocentric glioma (AG), first described in 2005, was included as a distinct entity in the 2007 World Health Organization Classification of Tumors of the Central Nervous System. It is a very rare cerebrocortical tumor mainly affecting children and young adults with a history of intractable partial seizures. The histopathological features of this entity are perivascular arrangement of monomorphic, bipolar spindled cells with subpial aggregation of tumor cells and variable neuroparenchymal colonization. Of uncertain histogenesis, this is a stable/slowly growing tumor. Prognosis following total surgical resection is favorable. We describe an AG in a 16-year-old, intellectually disabled, male patient, with psychosis. This is a rare presentation with only one such case in literature. Patient's symptoms ameliorated following surgery. [ABSTRACT FROM AUTHOR]

Introduction: In human beings the thyroid gland is one of the largest differentiated endocrine gland. The function of thyroid gland is to promote growth and development of the brain during foetal life and for the first few years of post-natal life. Aim: To study the histological features of thyroid gland in human Foetuses of different gestational age. Materials and Methods: Thyroid glands were dissected in 40 spontaneously aborted normal human Foetuses fixed in 5% formalin with gestational age ranging from 11 weeks to 38 weeks. After tissue processing, paraffin blocks were prepared. All sections were stained with Haematoxylin-Eosin. The sections of first two groups of this study (upto 16 weeks) were also stained with PAS to confirm the colloid. Results: Process of arrangement of thyroid follicles begins from 13th week onwards with gradual increase in their number and size. First appearance of colloid in follicles (Thin rim) was observed at 14th week and was confirmed by PAS. Thickness of capsule and vascularity of the gland increased with advancement of gestational age. Parafollicular cells or C cells were found after 17th week of gestation. Conclusion: In the present study, pre-colloidal stage was seen before 13 weeks and linear but partially overlapping developmental stages like folliculogenesis, colloid formation and maturation of follicles were observed after 14th week of gestation. [ABSTRACT FROM AUTHOR]

Abstract Microcystic adnexal carcinoma (MAC) is a rare, infiltrating, locally aggressive cutaneous neoplasm of combined follicular and eccrine/apocrine histogenesis, usually presenting on the upper lip or face. Differentiation from other adnexal tumours is very important because the clinical management of these tumours is radically different, and misdiagnosis may lead to incorrect treatment. A case of recurrent MAC in the upper lip, treated with multiple excisions and postoperative radiation therapy (PORT), is presented herein. There have been no signs or symptoms of recurrence since the subsequent reconstructive surgery and PORT. Based on reports in the literature it appears that although immunohistochemistry can be helpful in distinguishing between MAC and other adnexal tumours, careful histopathological examination is essential for an accurate diagnosis. Perineural and intramuscular invasion strongly suggest the diagnosis of MAC. Its predilection for the facial area often limits the width of surgical excision. In such cases, PORT may be considered. [ABSTRACT FROM AUTHOR]

Dentigerous cyst (DC) and ossifying fibroma (OF) are intraosseous lesions of the jaw. Both are varied pathological entities with a wide spectrum of clinical and histological features along with distinct treatment plan and prognosis. While OF comes under fibro-osseous lesions of the jaws, DC is a developmental odontogenic cyst which is formed by the accumulation of fluid between reduced enamel epithelium and enamel or between layers of the enamel organ. This case report presents a rare display of two distinct pathologies synchronously and aims to discuss the possible histogenesis for the same. [ABSTRACT FROM AUTHOR]

I Sir i : Recently, genetic analyses of primary mucinous ovarian tumours (MOTs) have considerably enhanced our understanding of the biology of such neoplasms, supporting a progressive model of carcinogenesis from benign/borderline tumours to carcinomas.1 Nevertheless, the histogenesis of these neoplasms remains a subject of discussion, and several cell types of origin have been proposed; a proportion of these tumours are associated with Brenner (transitional cell) tumours, so some are believed to be derived from metaplastic mucinous epithelium lining cystic transitional cell nests (Walthard rests).2 Rarely, MOTs may arise in the context of ovarian teratoma. In such cases, genomic studies have shown the mucinous neoplasms to have identical genetic patterns to those of the adjacent teratoma, indicating a shared cell of origin.3,4 Ovarian teratomas are believed to develop from a retained oocyte within the ovary. [Extracted from the article]

This study reported the clinicopathological features, treatment and prognosis of nine cases of noncalcifying and Langerhans cell (LC)-rich calcifying epithelial odontogenic tumor (CEOT) collected from the English literature. Of the nine cases, seven were intraosseous and two were extraosseous. All nine tumors were found in Asian patients. The age of the nine patients ranged from 20 years to 58 years with a mean age of 41 years. There were five female and four male patients. The seven intraosseous cases included six in the anterior and premolar region of the maxilla and one in the posterior region and ascending ramus of the mandible. The two extraosseous cases were located at the upper lateral incisor and premolar gingivae, respectively. Of the seven intraosseous cases, five showed unilocular and two multilocular radiolucency without foci of calcification. Six of the seven intraosseous cases showed resorption of the tooth roots in the tumor-involved region. Histologically, noncalcifying and LC-rich CEOTs were composed of small nests and thin strands of tumor epithelial cells with a relatively high number of LCs among them. This was the reason why we classed these nine cases as noncalcifying and LC-rich CEOTs. Two extraosseous cases received total excision of the gingival mass. For the seven intraosseous cases, four accepted partial maxillectomy or mandibulectomy, two received total excision or enucleation, and one underwent curettage. The six cases with the follow-up information available showed no tumor recurrence after a follow-up period of 6 months to 10 years.

Background and aims: Human fetal stomach starts developing at 4th week of gestational age. The precise knowledge of development of gastric mucosa is important for better understanding, diagnosis and treatment of different clinical conditions like Intestinal metaplasia, pernicious anaemia, heterotopic pancreatic tissue, atrophic gastritis etc. All these conditions are related to anomalous histogenesis of stomach. The aim of the study was to find out development of lining epithelium, gastric pits and glands and their ratio, time of appearance of different gastric mucosal cells in different weeks of gestation. Materials and methods : Sixty three normal fresh aborted fetuses were collected from obstetrics and gynaecology department of Regional Institute of Medical Sciences, Imphal. The fetuses were dissected and stomach was gently taken out, fixed in 10% normal saline and Bouin’s fluid followed by processing of the tissue. Staining was done with Haematoxylin and Eosin and Masson’s Trichrome. Results : The lining epithelium of stomach was seen to be simple cuboidal at 15 to 16 weeks which changed to columnar at 17th week of age. Gastric pits were seen to be very shallow in fundic part at 15th week and attained adult pattern by 28th week where as in pyloric part pits were deeper than fundic part from 17th week onwards. Parietal cells were first appreciated by 19th-20th week, chief cells and mucous neck cell were first seen by 25th-26th and 23rd-24th weeks respectively. Entero- endocrine cells were seen from 26th week onwards. No finding was suggestive of intestinal metaplasia or heterotopic pancreatic tissue or any other histogenetic anomaly. Conclusion : Very few studies have been conducted so far regarding histogenesis of human fetal stomach in India. The present study is expected to supplement known data and knowledge regarding histogenesis of human fetal stomach and help in diagnosis and treatment of related congenital anomalies.

Epidermoid cysts, which constitute 1% of all testicular tumors, are considered to be benign even though histogenesis is not clear. Patients usually suffer from painless scrotal mass or this mass is realized during the routine physical examination. Hematospermia may be a finding for both benign and malignant testicular tumors. Many authors advocate the testicular sparing surgery in the treatment but epidermoid cysts are usually treated with radical inguinal orchiectomy, because of the difficulties in the diagnosis, concurrence of the malignant tumors, and the debate on the histogenesis. [ABSTRACT FROM AUTHOR]

Merkel cell carcinoma (MCC) is an aggressive skin cancer frequently caused by the Merkel cell polyomavirus (MCPyV). It is still under discussion, in which cells viral integration and MCC development occurs. Recently, we demonstrated that a virus-positive MCC derived from a trichoblastoma, an epithelial neoplasia bearing Merkel cell (MC) differentiation potential. Accordingly, we hypothesized that MC progenitors may represent an origin of MCPyV-positive MCC. To sustain this hypothesis, phenotypic comparison of trichoblastomas and physiologic human MC progenitors was conducted revealing GLI family zinc finger 1 (GLI1), Keratin 17 (KRT 17), and SRY-box transcription factor 9 (SOX9) expressions in both subsets. Furthermore, GLI1 expression in keratinocytes induced transcription of the MC marker SOX2 supporting a role of GLI1 in human MC differentiation. To assess a possible contribution of the MCPyV T antigens (TA) to the development of an MC-like phenotype, human keratinocytes were transduced with TA. While this led only to induction of KRT8, an early MC marker, combined GLI1 and TA expression gave rise to a more advanced MC phenotype with SOX2, KRT8, and KRT20 expression. Finally, we demonstrated MCPyV-large T antigens’ capacity to inhibit the degradation of the MC master regulator Atonal bHLH transcription factor 1 (ATOH1). In conclusion, our report suggests that MCPyV TA contribute to the acquisition of an MC-like phenotype in epithelial cells.