Multiple Lobules Research Articles

Overexpression of the Pituitary Tumor Transforming Gene Induces p53-dependent Senescence through Activating DNA Damage Response Pathway in Normal Human Fibroblasts

Pituitary tumor transforming gene (PTTG1, securin) is involved in cell-cycle control through inhibition of sister-chromatid separation. Elevated levels of PTTG1 were found to be associated with many different tumor types that might be involved in late stage tumor progression. However, the role of PTTG1 in early stage of tumorigenesis is unclear. Here we utilized the adenovirus expression system to deliver PTTG1 into normal human fibroblasts to evaluate the role of PTTG1 in tumorigenesis. Expressing PTTG1 in normal human fibroblasts inhibited cell proliferation. Several senescence-associated (SA) phenotypes including increased SA-beta-galactosidase activities, decreased bromodeoxyuridine incorporation, and increased SA-heterochromatin foci formation were also observed in PTTG1-expressing cells, indicating that PTTG1 overexpression induced a senescent phenotype in normal cells. Significantly, the PTTG1-induced senescence is p53-dependent and telomerase-independent, which is distinctively different from that of replicative senescence. The mechanism of PTTG1-induced senescence was also analyzed. Consistent with its role in regulating sister-chromatid separation, overexpression of PTTG1 inhibited the activation of separase. Consequently, the numbers of cells with abnormal nuclei morphologies and chromosome separations were increased, which resulted in activation of the DNA damage response. Thus, we concluded that PTTG1 overexpression in normal human fibroblasts caused chromosome instability, which subsequently induced p53-dependent senescence through activation of DNA-damage response pathway.

Solitary synovial osteochondroma

Solitary synovial osteochondroma (SSO) is a rare variant of extraskeletal osteochondroma. The aim of this study was to review 5 cases of SSO, including clinical, radiographic, and histopathologic features. Five cases of SSO were retrieved from our files. Histopathologic and radiographic findings were reviewed, and a clinicopathologic correlation was performed. Patients' ages ranged from 33 to 63 years. Knee mass was the most common presentation. All cases were well circumscribed and had multiple cartilaginous lobules surrounded by fibroadipose tissue. Microscopically, lobulated adult-type hyaline cartilage with central calcification was noted. Cytologic atypia was present in one case, but malignant features were absent. Two cases were suggestive of chondrosarcoma on imaging studies. Patients underwent surgery, which was curative in cases for which follow-up was available. In conclusion, SSO is a rare lesion that may mimic low-grade chondrosarcoma at times. Correct recognition of SSO depends on radiographic and clinicopathologic analysis.

A Mixed Apocrine Gland Tumor with Metastases to the Bone and Bone Marrow in a Miniature Poodle

A 10-year-old female miniature poodle had a mass in its carpal joint of the left forelimb. The tumor was divided into small multiple lobules by delicate connective tissues, and necroses were found in some of the central lobules. In some connective stromal areas, chondroid and osteoid tissues were formed. The tumor cells were similar to the structure of apocrine gland epithelial cells with apical blebs resembling apocrine secretion and eosinophilic secretary materials within the luminal space, and spindle cells were sometimes found in the basal area of the glandular structure. In some areas, tumor cells invaded in the blood vessels, bone and bone marrow. Immunohistochemically, the tumor cells forming tubulo-acinar to solid structures were intensely positive for cytokeratin and keratin K8/K18, and the spindle cells were positive for vimentin and alpha-smooth muscle actin. This case was diagnosed as a malignant mixed apocrine gland tumor with metastases to the bone and bone marrow.

Multilobular tumour of the caudal cranium causing severe cerebral and cerebellar compression in a dog

Multilobular tumour of bone (MTB) is an uncommon tumour and is usually located in the skull. A 13-year-old mixed breed dog was presented with a two-week history of progressively worsening vestibular dysfunction and cognitive abnormalities; it appeared demented and showed asymmetric ataxia and hypermetria of all limbs. The owner opted to have the animal euthanised. Necropsy revealed a large mass occupying the right occipital, parietal and temporal bones, severely compressing the cerebellum and the right occipital lobe. Histologically, it was characterised by the presence of multiple lobules containing osteoid or cartilage and separated by fibrous septae, features typical of MTB. Lung metastases were evident. To our knowledge, this is the first report of an MTB causing both severe cerebral and cerebellar compression and the second detailed report of an MTB of the occipital bone. MTB should be included in the differential diagnosis of bone tumours as well as in cases with central vestibular disease.

Aggressive digital papillary adenocarcinoma on the palm with pulmonary metastases

A 41-year-old Japanese male had aggressive digital papillary adenocarcinoma with pulmonary metastases. He had an asymptomatic, solitary, dome-shaped, skin-colored firm nodule on his left palm for half year. The tumor consisted of multiple lobules of anaplastic epithelial cells with central necrosis. The neoplastic cells were immunohistochemically positive for cytokeratin and S-100 protein. Two years after the lesion was removed, pulmonary nodular lesions were found on chest X-ray. On histopathological examination, the pulmonary biopsy specimens showed lobular proliferation of acantholytic tumor cells and some ductal structures associated with papillary projections. Five years after the initial removal of the lesion, the patient was referred to our hospital because of a recurrent skin nodule on his left palm. The recurrent skin tumor was found to have lobular proliferation of anaplastic cells. On immunohistochemistry, the pulmonary metastasis and the palmar skin nodules were identical. The tumor was diagnosed as an aggressive digital papillary adenocarcinoma. This report is a rare case of aggressive digital papillary adenocarcinoma that was diagnosed based on the histopathology of the pulmonary metastases, which showed ductal structures associated with papillary projections.

Over-expression of GFP-FEZ1 causes generation of multi-lobulated nuclei mediated by microtubules in HEK293 cells

FEZ1 (Fasciculation and elongation protein zeta 1) is an ortholog of the Caenorhabditis elegans protein UNC-76, involved in neuronal development and axon outgrowth, in that worm. Mammalian FEZ1 has already been reported to cooperate with PKC-zeta in the differentiation and polarization of PC12 neuronal cells. Furthermore, FEZ1 is associated with kinesin 1 and JIP1 to form a cargo-complex responsible for microtubule based transport of mitochondria along axons. FEZ1 can also be classified as a hub protein, since it was reported to interact with over 40 different proteins in yeast two-hybrid screens, including at least nine nuclear proteins. Here, we transiently over-expressed GFP-FEZ1full in human HEK293 and HeLa cells in order to study the sub-cellular localization of GFP-FEZ1. We observed that over 40% of transiently transfected cells at 3 days post-transfection develop multi-lobulated nuclei, which are also called flower-like nuclei. We further demonstrated that GFP-FEZ1 localizes either to the cytoplasm or the nuclear fraction, and that the appearance of the flower-like nuclei depends on intact microtubule function. Finally, we show that FEZ1 co-localizes with both, α- and especially with γ-tubulin, which localizes as a centrosome like structure at the center of the multiple lobules. In summary, our data suggest that FEZ1 has an important centrosomal function and supply new mechanistic insights to the formation of flower-like nuclei, which are a phenotypical hallmark of human leukemia cells.

Ultrasound and MRI findings in appendicular and truncal fat necrosis

The objective was to evaluate ultrasound and MRI in clinical appendicular and truncal fat necrosis. Thirty-three patients (14 men, 19 women, median age 55, range 29-95) were retrospectively evaluated. Histologically, three groups were seen: Group 1 (n = 18) consisted of patients with subcutaneous masses with septal and extrinsic oedema; in Group 2 (n = 11) necrosis occurred within lipomatous tumours and little oedema; and in Group 3 (n = 4) there were large complex masses consistent with Morel-Lavallée lesions. Two experienced radiologists reviewed MR (n = 30) and ultrasound (n = 32) images with consensus agreement. MRI was performed on a 1.5T system with T1-weighted, T2-weighted fat-suppressed and T1-weighted fat-suppressed post-intravenous gadolinium sequences obtained in two orthogonal planes. Ultrasound (linear 5- to 13.5-MHz probe) was performed in the longitudinal and short axis. Anatomical position, size, shape (oval, linear, ill-defined), internal architecture (lobules, septi or stranding), intrinsic signal characteristics, presence of surrounding pseudocapsule, extrinsic linear stranding and vascularity (gadolinium enhancement or power Doppler) were recorded. Anatomical locations were buttock/thigh (n = 17), leg (n = 6), upper limb (n = 5) and thoracic/abdominal wall (n = 5) with the majority of lesions (30 out of 33) oval/linear in shape. On ultrasound and MRI most lesions showed internal fat lobules, intervening septi and a surrounding pseudocapsule. Fat necrosis can usually be identified as containing multiple fat lobules on ultrasound and MRI despite a varying degree of inflammatory change surrounding and within the mass.

Primary cavernous hemangioma of thyroid gland

We report a case of cavernous hemangioma presenting as a case of solitary nodule of thyroid.A 25-year-old male presented with a slowly growing solitary swelling in front of neck of 16 years duration. There was no history of pain over the swelling, change in voice or dyspnea. On clinical examination, a 6 × 4 cm irregular, hard, freely mobile swelling could be felt in the thyroid region. Ultrasonography (USG) showed a single hypoechogenic mass in the left lobe of the thyroid with coarse calcifications. X-ray of neck also showed coarse calcifications [Figure 1]. Computed tomography (CT) scan showed a heterogeneously enhancing mass of 4.9 × 4.4 cm diameter in the left lobe of the thyroid deviating the trachea to the right. Multiple dense calcific densities were noted in the nodule [Figure 2]. Fine needle aspiration cytology (FNAC) of the mass was attempted twice but was inconclusive and only blood could be aspirated. The patient was euthyroid and showed no signs of local spread or lymphadenopathy. Surgery in the form of left hemithyroidectomy was done. Peroperatively, tumor mass was found to be hard in consistency and well encapsulated. Gross pathology showed a well-circumscribed nodule with hemorrhagic and calcified areas. On histopathology, nodule was divided into multiple lobules with areas of hemorrhage, fibrosis, hyalinization and calcifications. Some of these calcifications were located in dilated vessels and classical cavernous vascular spaces could be seen [Figure 3]. A diagnosis of primary intrathyroid cavernous hemangioma was made.Lesions similar to hemangiomas secondary to FNAC have been reported. These have been ascribed to vascular proliferation in organized hematoma following the FNAC leading to a histological resemblance to cavernous hemangioma.

Recurrence Rate of Endometriomas Following a Laparoscopic Cystectomy

Laparoscopic cystectomy (LC) is at present viewed as the first-line means of diagnosing and treating endometriosis. This prospective study sought to identify factors related to postoperative recurrence in 315 women with endometriosis whose mean age was 31 years and who were followed up for an average of 21 months following LC. The procedure was performed using transvaginal ultrasonography. Four experienced gynecologists-not the ones who performed LC-evaluated the patients at 6-month intervals. Recurrent disease was defined as a diffuse, hypoechoic area whose long axis extended for at least 2 cm. Severity of disease was assessed using the revised American Society of Reproductive Medicine (r-ASRM) score. Bilateral LC was carried out in 102 patients and hemilateral LC in 213. The overall rate of recurrent disease was 16%, and the estimated cumulative recurrence rate for all patients 5 years after LC was 32%. The 51 women who became pregnant included 36 of 141 whose chief complaint at the time of primary surgery was sterility (25.5%). In comparison, 9% of women who did not complain of sterility became pregnant. Recurrent disease was relatively frequent in younger patients and those with more severe disease as indicated by their r-ASRM scores. Neither the size of cysts nor the presence of multiple lobules correlated significantly with recurrent disease. Patients undergoing hemilateral LC had a 5% rate of recurrence in the ovary that, at the time of initial surgery, appeared to be normal. In this prospective study, younger women with endometriosis and those with severe disease were at the highest risk of developing recurrent disease. It is likely that recurrences include both cysts that form spontaneously and others that develop from residual disease in lesions treated by cystectomy.

Colonic Lipoma With Intussusception

A 51-year-old woman was admitted to the hospital with a 20-day history of intermittent abdominal cramping. Her stools had decreased in volume and had become watery. Physical examination revealed no fever or palpable mass. Computed tomography in the axial plane showed an intussusception of the transverse colon due to a primary mass with dominant fatty density. The relationship of the intussusception to the mass was well delineated on oblique multiplanar reformation, and a diagnosis of colonic lipoma was considered. The patient's obstructive symptoms resolved spontaneously, and she was hesitant about undergoing surgery. However, recurrence of her symptoms a few days later prompted exploratory laparotomy, which revealed a long-stalked mass approximately 7 × 6 × 5 cm at the transverse colon near the hepatic flexure. Resection of the tumor revealed multiple yellowish lobules. Pathologic examination disclosed a lipoma with no evidence of malignancy. Colonic lipomas are relatively rare and frequently asymptomatic. Most gastrointestinal lipomas arise in the submucosa. The colon is commonly affected, followed by the small intestine and then the stomach. Large lipomas may be associated with complications such as intussusception or intestinal bleeding.1Kabaalioglu A Gelen T Aktan S Kesici A Bircan O Luleci E Acute colonic obstruction caused by intussusception and extrusion of a sigmoid lipoma through the anus after barium enema.Abdom Imaging. 1997; 22: 389-391Crossref PubMed Scopus (12) Google Scholar Colonoscopic biopsy is usually performed to confirm the nature of the tumor. However, inadequate tissue samples often indicate nonspecific colitis because of adjacent mucosal inflammation produced by the lipoma.2Zhang H Cong JC Chen CS Qiao L Liu EQ Submucous colon lipoma: a case report and review of the literature.World J Gastroenterol. 2005; 11: 3167-3169Crossref PubMed Scopus (52) Google Scholar Computed tomography clearly reveals the characteristic fatty densitometric features of lipomas.3Liessi G Pavanello M Cesari S Dell'Antonio C Avventi P Large lipomas of the colon: CT and MR findings in three symptomatic cases.Abdom Imaging. 1996; 21: 150-152Crossref PubMed Scopus (41) Google Scholar Most lipomas demonstrate homogeneous fatty density with a thin fibrous septa, depending on the tumor size. If prominent fibrous septa and nodularity are evident, the most imperative differential diagnosis is a well-differentiated liposarcoma, despite the few reports of gastrointestinal liposarcomas in the literature.4Pereira JM Sirlin CB Pinto PS Casola G CT and MR imaging of extrahepatic fatty masses of the abdomen and pelvis: techniques, diagnosis, differential diagnosis, and pitfalls.Radiographics. 2005; 25: 69-85Crossref PubMed Scopus (137) Google Scholar

Colonic Lipoma With Intussusception

A 51-year-old woman was admitted to the hospital with a 20-day history of intermittent abdominal cramping. Her stools had decreased in volume and had become watery. Physical examination revealed no fever or palpable mass. Computed tomography in the axial plane showed an intussusception of the transverse colon due to a primary mass with dominant fatty density. The relationship of the intussusception to the mass was well delineated on oblique multiplanar reformation, and a diagnosis of colonic lipoma was considered. The patient's obstructive symptoms resolved spontaneously, and she was hesitant about undergoing surgery. However, recurrence of her symptoms a few days later prompted exploratory laparotomy, which revealed a long-stalked mass approximately 7 × 6 × 5 cm at the transverse colon near the hepatic flexure. Resection of the tumor revealed multiple yellowish lobules. Pathologic examination disclosed a lipoma with no evidence of malignancy. Colonic lipomas are relatively rare and frequently asymptomatic. Most gastrointestinal lipomas arise in the submucosa. The colon is commonly affected, followed by the small intestine and then the stomach. Large lipomas may be associated with complications such as intussusception or intestinal bleeding.1Kabaalioglu A Gelen T Aktan S Kesici A Bircan O Luleci E Acute colonic obstruction caused by intussusception and extrusion of a sigmoid lipoma through the anus after barium enema.Abdom Imaging. 1997; 22: 389-391Crossref PubMed Scopus (12) Google Scholar Colonoscopic biopsy is usually performed to confirm the nature of the tumor. However, inadequate tissue samples often indicate nonspecific colitis because of adjacent mucosal inflammation produced by the lipoma.2Zhang H Cong JC Chen CS Qiao L Liu EQ Submucous colon lipoma: a case report and review of the literature.World J Gastroenterol. 2005; 11: 3167-3169Crossref PubMed Scopus (52) Google Scholar Computed tomography clearly reveals the characteristic fatty densitometric features of lipomas.3Liessi G Pavanello M Cesari S Dell'Antonio C Avventi P Large lipomas of the colon: CT and MR findings in three symptomatic cases.Abdom Imaging. 1996; 21: 150-152Crossref PubMed Scopus (41) Google Scholar Most lipomas demonstrate homogeneous fatty density with a thin fibrous septa, depending on the tumor size. If prominent fibrous septa and nodularity are evident, the most imperative differential diagnosis is a well-differentiated liposarcoma, despite the few reports of gastrointestinal liposarcomas in the literature.4Pereira JM Sirlin CB Pinto PS Casola G CT and MR imaging of extrahepatic fatty masses of the abdomen and pelvis: techniques, diagnosis, differential diagnosis, and pitfalls.Radiographics. 2005; 25: 69-85Crossref PubMed Scopus (137) Google Scholar

Structural and ultrastructural features of boar seminal vesicles

The morphological features of boar seminal vesicles were examined by light and transmission microscopy. Boar seminal vesicles consist of glandular tissue arranged in multiple lobules containing a system of ramified secretory tubules. The secretory tubules are composed of a mucosa formed by an epithelium and an underlying lamina propria and, are surrounded by a muscular layer. The epithelium is made up of columnar cells and occasional basal cells. Mast cells are frequently found among epithelial cells. Three types of columnar cells, considered different stages of the secretory cell cycle, are present: principal cells, clear cells and dense cells. Principal cells are functionally differentiated cells characterised by abundant mitochondria, great development of the rough endoplasmic reticulum and presence of secretory granules in their cytoplasm. The apical surface of many principal cells shows apical blebs filled with PAS-positive material. No acid mucosubstances are detected. Microvilli cover the apical surface except in the apical blebs. Dense cells, arranged between principal cells, are also functional differentiated cells but with signs of cellular degeneration. Clear cells are an initial differentiated stage of columnar cells and are characterised by the presence of a poorly developed rough endoplasmic reticulum and by the absence of secretory granules. Proliferating cells are present among columnar cells. Basal cells contain scarce cytoplasm, few organelles and no secretory granules. The lack of mitotic activity in these cells suggests that they do not act as precursors of columnar cells.

Multilobular tumor of the mandible in a Pekingese dog

Multilobular tumor of bone detected in a 2.5-year-old male Pekingese dog is reported. Grossly, the neoplasm consisted of multiple, variably sized, gritty, grayish-white to yellow nodules separated by thick collagenous septa. Histologically, these nodules contained multiple lobules of irregularly shaped and sized islands of well-differentiated osteoid and cartilage, separated by anastomosing fibrovascular septa. Chondrocytes and osteocytes were observed in the lacunae and in more osseous islands in the lobule, respectively. These lobules were surrounded by mesenchymal spindle cells. Mitotic figures were not evident. The neoplastic pattern was consistent with that of a multilobular bone tumor. Diagnosis was based on gross and light microscopic findings. The cause of this neoplasm was not determined.

Structural and ultrastructural features of boar bulbourethral glands

The morphological features of boar bulbourethral glands were examined by light and transmission microscopy. Bulbourethral glands are compound tubuloalveolar glands surrounded by a capsule of dense connective tissue and arranged in multiple lobules formed by endpieces and excretory ducts. Endpieces and excretory ducts are both lined by a single epithelium of mucous cells with a basal nucleus. Epithelial cells accumulate secretory granules containing neutral and carboxylated acid mucosubstances and a small amount of sulphated acid mucosubstances. The ultrastructure of epithelial cells varies according to the secretory cycle. In initial stages, the cells show a columnar shape and secretory granules unevenly distributed in the cytoplasm. As the synthesis of mucosubstances progresses, the amount of the secretory granules increases and the cellular shape becomes pyramidal. Secretory granules can contain inclusions and present differences among them according to their different phases of formation. In pyramidal cells, secretory products are released into the lumen by a merocrine mechanism.

Lymphoepithelioma‐Like Carcinoma of the Skin: A Case Report

Lymphoepithelioma‐like carcinoma of the skin is a rare tumor with a microscopic resemblance to lymphoepitheliomatous carcinoma of the nasopharynx. We present a 93‐year‐old man with papules on the left auricle to the cheek that were gradually enlarged. By the time of a biopsy, it grew to a 5.0 × 3.0 × 2.8 cm dark red mass, and necrotic debris was attached to the surface. Histologically, a relatively well‐demarcated, dermal‐hypodermic multiple lobules were composed of irregular islands of atypical epithelial cells. The uniform tumor cells had moderate amounts of lightly eosinophilic cytoplasm and vesicular nuclei with one or two prominent nucleoli. A dense lymphocytic infiltrate was present within the neoplastic islands, obscuring the epithelial component. The neoplastic cells were unconnected to the overlying epidermis. Neither squamous nor glandular differentiation was present. Immunohistochemically, the neoplastic cells were positive for epithelial membrane antigen and cytokeratin, and negative for latent membrane protein 1. No Epstein‐Barr virus‐encoded RNA (EBER) was detected by in situ hybridization. The negativity for Epstein‐Barr virus may be a help in the differential diagnosis from metastatic undifferentiated nasopharyngeal carcinoma, which is uniformly positive for EBER.

MR and MR angiography characterization of soft tissue vascular malformations

Hemangioma is an abnormal proliferation of blood vessels that may occur in any vascularized tissue. Different classifications separate vascular lesions of soft tissues into hemangiomas and vascular malformations on the basis of their natural history, location, cellular turnover, and histology. Soft-tissue vascular malformations are relatively common. These lesions can be categorized on MR imaging because of their typical appearance as multiple lobules with fat overgrowth and serpentine channels, depending on the vascular flow. The combination of conventional MR and MR angiography (MRA) enable the differentiation between low-flow and high-flow vascular malformations and allows a noninvasive diagnostic strategy. This article reviews the MR and MRA imaging characteristics of soft-tissue hemangiomas to provide a helpful guide for radiologists to perform a more specific diagnosis and better management of these anomalies.

First histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion: differential diagnosis of benign and malignant notochordal lesions

The first histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion is presented and the differential diagnosis between benign and malignant notochordal lesions is discussed. A 57-year-old man presented with a classic chordoma in the coccyx. The resected specimen demonstrated a small intraosseous benign notochordal lesion in the coccyx, which was adjacent to the classic chordoma. Also seen were two separate, similar benign lesions in the sacrum. The classic chordoma consisted of multiple lobules that were separated by thin fibrous septa and that showed cords or strands of atypical physaliphorous cells set within an abundant myxoid matrix. In contrast, the benign lesions consisted of intraosseous sheets of bland physaliphorous cells without any extracellular matrix. The affected bone trabeculae showed sclerotic reactions. It was concluded that benign and malignant notochordal lesions can be distinguished microscopically.

The Entire Trajectories of Single Olivocerebellar Axons in the Cerebellar Cortex and their Contribution to Cerebellar Compartmentalization

The functional partitioning of the cerebellar cortex depends on the projection patterns of its afferent and efferent neurons. However, the entire morphology of individual projection neurons has been demonstrated in only a few classes of neurons in the vertebrate CNS. To investigate the contribution of the projection pattern of individual olivocerebellar axons to the cerebellar functional compartmentalization, we labeled individual olivocerebellar axons, which terminate in the cerebellar cortex as climbing fibers, with biotinylated dextran amine injected into the inferior olive in the rat, and completely reconstructed the entire trajectories of 34 olivocerebellar axons from serial sections of the cerebellum and medulla. Single axons had seven climbing fibers on average, which terminated at similar distances from the midline in a single or in multiple lobules. Cortical projection areas of adjacent olivary neurons were clustered as narrow but separate longitudinal segments and often innervated by collaterals of single neurons. Comparison of the cerebellar distribution of olivocerebellar axons arising from different sites within a single olivary subnucleus indicated that slightly distant neurons projected to complementary sets of such segments in a single longitudinal band. Several of these longitudinal bands formed a so-called parasagittal zone innervated by a subnucleus of the inferior olive. Single olivocerebellar axons projected rostrocaudally to segments within a single band but did not project mediolaterally to multiple bands. These results suggest fine substructural organization in the cerebellar compartmentalization that may represent functional units.

MR Imaging of Sacrococcygeal Pilonidal Sinus

Purpose: The purpose of this study is to evaluate the characteristic MR findings of sacrococcygeal pilonidal sinus. Materials and Methods: Eight MR images of pathologically proven sacrococcygeal pilonidal sinus were retro-spectively reviewed [M: F = 7: 1; age range 9-41 (median, 17) years]. In all cases, a sacrococcygeal mass was present. Five of the eight patients experienced pain, and in three was discharge. MR findings were evaluated with regard to the location and extent of the lesion, and the presence of sinus or cyst, and the results were com-pared with the pathologic findings. Results: According to the clinical manifestations, each case was assigned to one of four groups: the first type (n= 3) showed dermal thickening with subcutaneous fatty infiltration of the ipsilateral natal cleft while patholog-ically, a follicular cyst with dermal fibrosis and multiple fatty lobules with fibrous septa were found to be pre-sent. In the second type (n = 3), fluid was observed in the sinus tract, while the pathologic findings demon-strated the presence of an abscess in this area. In the third type (n = 1), a cystic lesion with air-fluid level was present; pathologically, an abscess was revealed. The fourth type (n = 1) showed only a low signal intensity sinus tract on both T1 and T2-weighted images, while the pathologic findings indicated the presence of hairs and follicles within the tract. Conclusion: The MR findings of sacrococcygeal pilonidal sinus depend on the clinical manifestation and include subcutaneous fatty infiltration, a sinus tract with or without fluid retention, and a cystic lesion with air fluid level. These findings could be helpful for differentiating between this and other sacrococcygeal lesions.

Projection patterns of single mossy fibers originating from the lateral reticular nucleus in the rat cerebellar cortex and nuclei

Projection of neurons in the lateral reticular nucleus (LRN) to the cerebellar cortex (Cx) and the deep cerebellar nuclei (DCN) was studied in the rat by using the anterograde tracer biotinylated dextran amine (BDA). After injection of BDA into the LRN, labeled terminals were seen bilaterally in most cases in the vermis, intermediate zone, and hemisphere of the anterior lobe, and in various areas in the posterior lobe, except the flocculus, paraflocculus, and nodulus. Areas of dense terminal projection were often organized in multiple longitudinal zones. The entire axonal trajectory of single axons of labeled LRN neurons was reconstructed from serial sections. Stem axons entered the cerebellum through the inferior cerebellar peduncle (mostly ipsilateral), and ran transversely in the deep cerebellar white matter. They often entered the contralateral side across the midline. Along the way, primary collaterals were successively given off from the transversely running stem axons at almost right angles to the Cx and DCN, and individual primary collaterals had longitudinal arborizations that terminated as mossy fibers in multiple lobules of the Cx. These collaterals arising from single LRN axons terminated bilaterally or unilaterally in the vermis, intermediate area, and sometimes hemisphere, and in different cerebellar and vestibular nuclei simultaneously. The cortical terminals of single axons appeared to be distributed in multiple longitudinal zones that were arranged in a mediolateral direction. All of the LRN axons examined (n = 29) had axon collaterals to the DCN. All of the terminals observed in the DCN and vestibular nuclei belonged to axon collaterals of mossy fibers terminating in the Cx.