Thymic carcinoma initially presented with geographic destruction of scapula in a child.

As the conventional histopathologic examination of thymic carcinoma (TC) is nonspecific, immunohistochemical studies along with correlative radiographic investigations are needed for its correct diagnosis. TC commonly occurs in the late 5th to early 6th decades of life but is extremely rare in childhood. It may be incidentally detected from chest radiographs taken as routine or for other reasons. However, most patients present with symptoms such as chest pain, cough, shortness of breath, dysphagia and hoarseness, which are directly attributable to the mediastinal mass. Although TC frequently invades the neighboring organs, pleura and pericardium and metastasizes to the lymph nodes, liver and lung at the time of the first diagnosis, initial or late metastasis to the bone has been seldom reported in adults. Indeed, the English literature revealed no earlier report on initial bony metastasis in a child to date. We report a case of TC in a 12-year-old boy who initially presented with scapular osteolysis masquerading as a primary bone tumor to emphasize the usefulness of combined imaging for staging and histologic studies, particularly for such an unexpected case.

Huge tophaceous pseudogout associated with tenosynovial chondromatosis arising from flexor digitorum tendon sheaths of the foot: a case report.

Synovial chondromatosis (SC) is a benign proliferative process of synovial tissue creating multiple cartilaginous nodules in joints. It most commonly occurs in the large joints of the knee, hip, and shoulder, uncommonly in the small joints of the hand and foot, and only rarely in the tenosynovial membrane of tendon sheath, termed tenosynovial chondromatosis (TC). Unlike SC, TC predisposes to the foot or hand. The rarity and unfamiliarity of imagers with TC, as well as the variability of its histologic features often lead to an erroneous diagnosis of extraskeletal chondroma or even chondrosarcoma as in the present case. Calcium pyrophosphate dehydrate (CPPD) crystals are usually deposited in the articular cartilage or periarticular structures such as synovium and capsule, and rarely in other soft tissue structures including bursa, tendon, subcutaneous tissue, and dura mater. CPPD crystals may also be deposited in extraskeletal chondroma and SC. We present an exceptionally rare case of huge tophaceous pseudogout associated with TC that is considered to arise from the flexor digitorum longus tendon sheaths of the foot, initially mistaken for a chondrosarcoma.

Kimura's disease involving a long bone.

Kimura's disease is a rare, benign lymphoproliferative disorder of unknown etiology. It occurs most often in Asian men, usually in the second or third decade of life. Most lesions occur in the head and neck followed by the axilla, groin, popliteal region, and arm. The lesions are commonly found in soft tissues. To the best of our knowledge, there has been only one case report of bone involvement in Kimura's disease presented on plain radiography. We report a case of Kimura's disease that involved the proximal meta-diaphysis of the humerus and adjacent soft tissue shown on radiography and MR imaging.

Use of the JL1 epitope, which encompasses the nonglycosylation site of CD43, as a marker of immature/neoplastic Langerhans cells.

Langerhans cell histiocytosis (LCH) is the collective designation for a group of proliferative disorders of antigen-presenting cells in the epidermis. Over the past several decades, the etiology of LCH has been a controversial issue, particularly with respect to the pathologic process, that is, whether it is a neoplastic or inflammatory process. Recently, it was reported that the JL1 epitope, which encompasses the nonglycosylation site of CD43, is only exposed in the precursor stages of hematopoietic cells or in neoplastic conditions. We sought to investigate the possible utility of the JL1 monoclonal antibody as a diagnostic marker of LCH. In this study, we compared the staining characteristics of antibodies against the JL1 epitope with those of langerin and CD1a, which are widely used for the diagnosis of LCH. We found substantial differences in the staining patterns of these markers. The JL1 epitope could be bound by antibodies in cases of LCH and Langerhans cell (LC) sarcoma. In non-neoplastic lesions, JL1-positive LCs were found only in dermatitis, reflecting the immaturity of LCs in inflamed skin. However, anti-langerin antibodies were able to identify any form of LC, including those in normal skin, dermatitis, dermatopathic lymphadenopathy, and LCH. On the basis of these findings, we propose that the anti-JL1 antibody is a specific marker of immaturity, a feature that is shared in neoplastic LCs, and can be useful in the diagnosis of LCH.

CD99-dependent expansion of myeloid-derived suppressor cells and attenuation of graft-versus-host disease.

CD99 is involved in many cellular events, such as the generation of Hodgkin and Reed-Sternberg cells, T cell costimulation, and leukocyte transendothelial migration. However, these studies have been limited to in vitro or in vivo experiments using CD99-deficient cell lines or anti-CD99 antibodies. In the present study, using CD99-deficient mice established by the exchangeable gene trap method, we investigated the physiologic function of murine CD99. In a B6 splenocytes → bm12 graft-versus-host disease model, wild-type cells were minimally lethal, whereas all mice that received CD99-deficient donor cells developed an early and more severe pathology. Graftversus-host disease in these mice was associated with insufficient expansion of myeloid-derived suppressor cells. This was confirmed by experiments illustrating that the injection of wild-type donor cells depleted of Mac-1(+) cells led to an almost identical disease course as the CD99-deficient donor system. Therefore, these results suggest that CD99 plays a crucial role in the attenuation of graft-versus-host disease by regulating the expansion of myeloid-derived suppressor cells.

Chromomycosis presenting as soft-tissue mass: report of a case with MRI features.

Chromomycosis is primarily a skin disease that superficially presents as slowly growing, verrucous lesions, often warty or cauliflower-like in appearance. It may occasionally create a flat, plaque-like lesion in the skin but deep-seated tumorous presentation has not previously been reported. As the lesion is limited to the cutaneous and superficial subcutaneous tissues, hitherto reported cases have been described from the view point of dermatology and, so, without MRI study. We report a patient with pathologically proven chromomycosis that produced a subcutaneous mass in the dorsum of the hand with an emphasis on MRI features.

The clinical features and pathophysiology of acute radiation dermatitis in patients receiving tomotherapy.

BACKGROUND: Radiation therapy (RT) including tomotherapy has been widely used to treat primary tumors, as well as to alleviate the symptoms of metastatic cancers. OBJECTIVE: The primary purpose of this study was to examine the characteristics of the clinical features and pathophysiological mechanisms associated with acute radiation dermatitis in cancer patients that received tomotherapy, and compare the results to patients treated by conventional radiation therapy. METHODS: The study population consisted of 11 patients that were referred to the dermatology department because of radiation dermatitis after receiving tomotherapy; all patients were evaluated for clinical severity. The patients were assessed and identified using the National Cancer Institute Common Toxicity Criteria version (CTC) 3.0. We performed biopsies of the skin lesions that were examined for apoptosis using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling (TUNEL) assay and stained immunohistochemically with monoclonal antibodies to CD8, CD4 and TGF-beta. As a positive control, patients with radiation dermatitis treated with conventional radiation therapy were also studied. RESULTS: THE RESULTS OF THE CLINICAL FEATURES OF THE SKIN OF TOMOTHERAPY PATIENTS WERE THE FOLLOWING: grade 1 (36%), grade 2 (55%) and other changes (9%). Among the population that had skin lesions due to acute radiation dermatitis, the mean number of positive cells per high power field (HPF) was the following: there were 30.50+/-7.50 TUNEL-positive cells, 34.60+/-12.50 CD8+ T cells, 5.19+/-3.17 CD4+ T cells and 9.95+/-1.33 TGF-beta positive cells measured per HPF. The mean number of positive cells per HPF for the patients that received conventional radiation therapy was: TUNLEL-positive cells in 7.5+/-1.64, CD8-, CD4- and TGF-beta-positive cells in 12.50+/-3.73, 3.16+/-1.47, 6.50+/-1.97. CONCLUSION: We found that the number of TUNEL-positive cells and CD8+ T cells were higher in the lesions of patients receiving tomotherapy compared to the lesions of the patients receiving conventional radiation therapy. These findings suggest that tomotherapy without dose modification may cause significantly more severe forms of radiation dermatitis by apoptosis and cytotoxic immune responses than conventional radiation therapy.