A west African ancestry-associated SNP on 8q24 predicts a positive biopsy in African American men with suspected prostate cancer following PSA screening.

BACKGROUND: African American (AA) men have the highest incidence and mortality rates of prostate cancer (PCa) among all racial groups in the United States. While race is a social construct, for AA men, this overlaps with west African ancestry. Many of the PCa susceptibility variants exhibit distinct allele frequencies and risk estimates across different races and contribute substantially to the large disparities of PCa incidence among races. We previously reported that a single-nucleotide polymorphism (SNP) in 8q24, rs7824364, was strongly associated with west African ancestry and increased risks of PCa in both AA and Puerto Rican men. In this study, we determined whether this SNP can predict biopsy positivity and detection of clinically significant disease (Gleason score [GS] ≥ 7) in a cohort of AA men with suspected PCa. METHODS: SNP rs7824364 was genotyped in 199 AA men with elevated total prostate-specific antigen (PSA) (>2.5 ng/mL) or abnormal digital rectal exam (DRE) and the associations of different genotypes with biopsy positivity and clinically significant disease were analyzed. RESULTS: The variant allele carriers were significantly over-represented in the biopsy-positive group compared to the biopsy-negative group (44% vs. 25.7%, p = 0.011). In the multivariate logistic regression analyses, variant allele carriers were at a more than a twofold increased risk of a positive biopsy (odds ratio [OR] = 2.14, 95% confidence interval [CI] = 1.06-4.32). Moreover, the variant allele was a predictor (OR = 2.26, 95% CI = 1.06-4.84) of a positive biopsy in the subgroup of patients with PSA < 10 ng/mL and normal DRE. The variant allele carriers were also more prevalent in cases with GS ≥ 7 compared to cases with GS < 7 and benign biopsy. CONCLUSIONS: This study demonstrated that the west African ancestry-specific SNP rs7824364 on 8q24 independently predicted a positive prostate biopsy in AA men who were candidates for prostate biopsy subsequent to PCa screening.

Primary Synovial Sarcoma of the Uterine Cervix: First Case Report.

Synovial sarcoma is a translocation associated soft tissue malignancy frequently affecting young adults. The classic translocation is t(X;18)(p11.2;q11.2): SS18-SSX1/2/4 fusion. Synovial sarcoma tends to favor the distal extremities but can also arise in other locations. To date, no case of primary synovial sarcoma of the uterine cervix has been reported. We report a 42-yr-old woman with no prior history who presented to clinic with vaginal spotting for 3 mo and was found to have a large mass in the uterine cervix. The mass was evacuated from the vagina and sent for pathologic diagnosis. Sections showed proliferation of monotonous spindle cells with scant eosinophilic cytoplasm, round to slightly irregular nuclei, variable nucleoli and frequent mitosis in a background of delicate capillary and occasional thick-walled vessels. No malignant epithelium was identified in the entire specimen. On immunohistochemical workup tumor cells were negative for pan cytokeratin, OSCAR, EMA, chromogranin, S100, SMA, desmin, myogenin, WT1, CD117, CD34, and BRG1. CD45 was positive in a few inflammatory cells. Cyclin D1 showed partial weak to moderate nuclear reactivity. CD99 demonstrated strong diffuse membranous reactivity and BCL-2 showed strong cytoplasmic staining in 60% of tumor cells. Florescence in situ hybridization results for EWSR1, BCOR, and CIC gene rearrangements were negative, however, florescence in situ hybridization results for SS18 (SYT) (18q11) gene rearrangement was positive. A diagnosis of monophasic synovial sarcoma was rendered. We review the differential diagnoses of tumors with similar morphology and discuss the diagnostic process. With this case report it is imperative to include synovial sarcoma in differential diagnosis list of sarcomas of uterus and cervix.

Reproducible evaluation of tumor-infiltrating lymphocytes (TILs) using the recommendations of International TILs Working Group 2014.

Tumor infiltrating lymphocytes (TILs) in breast cancer play an important role in predicting the outcome of breast cancer. The goal of our current study is to investigate the consistency and reproducibility of the recommendations published by the International TILs Working Group 2014 among pathology trainees and pathologists. Hematoxylin & Eosin (H&E) slides from 129 breast cancer cases (one slide each) from 2009 to 2014 were evaluated. Each case was blindly and independently reviewed by two observers following the International TILs Working Group 2014 recommendations. Three pathology trainees (PGY2, PGY3 and PGY4) and three pathologists (2 general pathologists and 1 breast pathologist) were involved in this study. Of the 129 cases, 10 (10/129, 7.8%) cases had TILs >50%, 90 (90/129, 69.8%) cases had <10% of TILs, and 29 (29/129, 22.4%) cases had TILs ranging from 10 to 50%. Our results showed that in 104 cases (104/129, 80.6%) the TILs percentage was identical between the 2 observers. In 18 cases (18/129, 14%), the difference between the two observers was by 10% and in 7 cases (7/129, 5.4%) there was a difference of 20% or more. The inter-observer kappa value was 0.776 between two observers, and the kappa score improved to 0.86 if using the 3 categoric groups (<10%, 10-50%, and >50%). Our study showed that the recommendations and instructions for TILs evaluation by the International TILs Working Group 2014 were sufficiently detailed to be applied for TILs evaluation in breast cancer.

Tumefactive foreign body giant cell reaction following high-pressure paint injection injury: A case report and review of literature.

High-pressure paint injection injury is an uncommon but well-described injury. The histologic features of long-term paint injection injury with retained material are less recognized. A 46-year-old male presented clinically as "recurrent giant cell tumor of tendon sheath." The right index finger demonstrated fusiform enlargement by a pigmented mass with diffuse infiltration into the soft tissue of the hand. Histologically the tumor showed multiple giant cells in a fibrotic stroma extending into the dermis. There were multiple types of foreign material including diffuse brown black pigment, weakly optically polarizing foreign material and white inclusions with a "train track" appearance. The cells were positive for CD68 and negative for S100 antigen. Further investigation revealed that the patient had a history of high-pressure paint injection injury to his digit 6 years prior. Foreign material injected under high pressure into tissues may result in a pseudo-neoplastic foreign body granulomatous reaction that can mimic giant cell tumor of tendon sheath. Our case demonstrates that this reaction can be florid and can have slow growth over years. A high index of suspicion, a good clinical history and careful examination can distinguish these 2 entities.

Cystic Encapsulated Papillary Carcinoma in the Male Breast: An Unusual Feature With a Diagnostic Challenge.

Papillary carcinoma in the male breast is uncommon. Here, we report a case of a large encapsulated papillary carcinoma (EPC) in a 62-year-old male. The patient presented with a left breast mass of 1-year duration and bloody nipple discharge for several days. Mammography and breast ultrasonography showed a large left breast mass. The initial biopsy demonstrated fat necrosis with acute and chronic inflammation only. Due to clinical suspicion, a repeat biopsy was performed and revealed scant fragments of papillary carcinoma in a background of inflammation. The patient underwent left total mastectomy. Grossly, the breast contained a 9.0 cm entirely cystic lesion lined by a hemorrhagic thick fibrotic wall. No solid area was identified in the cyst. The entire cyst wall was examined under microscopy; only a few sections with papillary carcinoma were identified. The lesion was confined to the cyst wall; so, a diagnosis of EPC was made. Compared to the previously reported EPC cases of male breast, the lesion of this case was unusually cystic, which making the diagnosis challenging. Therefore, awareness of this unusual feature, repeat biopsy when the pathology result is discordant, and extensive sampling of the lesion are essential for making the correct diagnosis and guiding patient management.

The impact of declining clinical autopsy: need for revised healthcare policy.

In Western countries, autopsy rates for patients deceased in hospitals have dropped to record lows, while the average frequency of major errors in clinical diagnoses has more than doubled during the same time period. Meanwhile, the Institute of Medicine and the U.S. Department of Health and Human Services have called attention to the high frequency of errors affecting patient safety, bringing the issue of public safety to the forefront of public health concerns. Although autopsies represent a vital tool for the acquisition of new medical knowledge and for medical quality assurance, health care professionals, insurers, and politicians apparently have not chosen the right approach to solve the problem of declining autopsy rates. The present article reviews the current status of clinical autopsies and addresses causes and consequences of their neglect and appeal the urgent need to revise the policy for clinical autopsy.

Tumor-Infiltrating Lymphocyte Volume Is a Better Predictor of Disease-Free Survival Than Stromal Tumor-Infiltrating Lymphocytes in Invasive Breast Carcinoma.

OBJECTIVES: Tumor-infiltrating lymphocytes (TILs) have recently emerged as a prognostic factor in breast cancer. In our previous study, we proposed that tumor stroma should also be considered in the calculation of TILs and we introduced tumor infiltration lymphocyte volume (TILV) in triple-negative breast cancer. METHODS: We assessed the disease-free survival predictive value of TILV in all subtypes of invasive breast carcinoma and compared the predictive value of TILV with TILs. Differences between disease-free survival curves were determined by using the log-rank test, and Kaplan-Meier survival plots were generated for both groups. RESULTS: TILV was significantly correlated with disease-free survival in both invasive ductal carcinoma (P = .03) and all subtypes of invasive breast carcinoma (P = .043), whereas TILs failed to show a statistical significance. CONCLUSIONS: Tumor-stroma ratio needs to be considered in estimation of tumor immunity, and TILV adds more predictive power to TILs.

Low Grade Carcinoma Ex-Pleomorphic Adenoma: Diagnosis and Diagnostic Challenges Caused by Fine Needle Aspiration: Report of Three Cases and Review of Literature.

Low grade carcinoma ex pleomorphic adenoma (LG CXPA) is a rare low grade malignant neoplasm arising from preexisting pleomorphic adenoma (PA). LG CXPA demonstrates no overt cytological atypia, and can be difficult to distinguish from cellular PA. Invasive growth is one of the hallmarks of LG CXPA, e.g., tumor extends beyond the capsule and into adjacent non-neoplastic tissue. However, it is known that capsular and vascular invasion, as well as the presence of stroma-rich PA in soft tissue without a capsule (pseudopodia) can be seen in PA. These histological findings have no prognostic significance and are not diagnostic of malignancy. In addition, recurrent PA typically presents as numerous nodules extending into soft tissue and skeletal muscle, which again are not considered malignant features. Thus, "infiltrative growth" of LG CXPA is difficult to define and diagnosis is challenging to many practicing pathologists. In this study, we report three cases of LG CXPA. We review the diagnostic criteria for LG CXPA, and discuss the diagnostic challenges caused by fine needle aspiration (FNA) changes. FNA is widely used as a cost-effective, quick and accurate method for diagnosing salivary gland lesions. Histological changes post-FNA are usually focal and mild, and are not causes of diagnostic difficulties. According to our knowledge, this is the first report of LG CXPA complicated with FNA changes.

P16-positive cystic squamous cell carcinoma in midline neck: metastasis from oropharynx or primary carcinoma arising from thyroglossal duct cyst?

Cystic squamous cell carcinoma (SCC) of the lateral neck is considered metastatic human papilloma-virus (HPV)-related oropharyngeal SCC (HPV-OPSCC) until proven otherwise. P16 immunohistochemistry is diffusely positive in those carcinomas and is used as a surrogate marker of active human papillomavirus (HPV) infection. Thyroglossal duct cysts (TDC) are one of the differential diagnoses for cystic neck lesions. SCC arising from TDC is extremely rare. In this study, we report a p16-positive cystic SCC located in the midline neck. Radiologic features and the presence of thyroid tissue in the cyst wall indicated that it was a TDC. The morphologic features of the lesion raised the question: is the carcinoma metastatic HPV-OPSCC? The HPV confirmative test, high-risk HPV RNA in situ hybridization, was negative. We then studied p16 immunohistochemistry in the squamous epithelium of benign TDC and found that rare benign TDC can show diffuse and strong p16 positivity.

Sclerosing Pneumocytoma: a Carcinoma Mimicker. A Case Report and Literature Review.

OBJECTIVES: Sclerosing pneumocytoma (SP) is a rare entity. Diagnosis of SP can be problematic especially on biopsy specimens, in particular, when the sample is obtained from the papillary component. METHODS: An asymptomatic 33 year-old female with no smoking history was incidentally found to have a lung mass. She was diagnosed to have well-differentiated adenocarcinoma with papillary features on biopsy. A lobectomy was performed. RESULTS: The circumscribed mass was composed predominately of papillary structures, with the "surface cuboidal cells" located on the surface of the papillae and "round cells" in the stalks of the papillae. Immunohistochemical staining demonstrated nuclear reactivity for TTF-1 in both cell types and Napsin A positivity only in "surface" cells. CONCLUSIONS: In evaluation of a lung biopsy from a mass with a predominantly papillary pattern, sclerosing pneumocytoma (sclerosing hemangioma in previous classifications) should always be in the differential diagnoses.

First Neonatal Demise with Travel-Associated Zika Virus Infection in the United States of America.

Zika virus is increasingly recognized as a fetal pathogen worldwide. We describe the first case of neonatal demise with travel-associated Zika virus infection in the United States of America, including a novel prenatal ultrasound finding. A young Latina presented to our health care system in Southeast Texas for prenatal care at 23 weeks of gestation. Fetal Dandy-Walker malformation, asymmetric cerebral ventriculomegaly, single umbilical artery, hypoechoic fetal knee, dorsal foot edema, and mild polyhydramnios were noted upon initial screening prenatal sonography at 26 weeks. A growth-restricted, microcephalic, and arthrogrypotic infant was delivered alive at 36 weeks but died within an hour despite resuscitation. The neonatal karyotype was normal. Flavivirus IgM antibodies were identified in the serum of the puerpera, once she disclosed that she had traveled from El Salvador to Texas in the early second trimester. Zika virus was identified in the umbilical cord and neonatal brain. Fetal arthritis may precede congenital arthrogryposis in cases of Zika virus infection and may be detectable by prenatal sonography. Physician and health care system vigilance is required to optimally address the significant and enduring Zika virus global health threat.

Inflammatory aneurysm of the ascending aorta.

Inflammatory aneurysms of the aorta are usually seen in the infrarenal abdominal aorta and very rarely in the ascending aorta. We present the case of a 76-year-old male with inflammatory aneurysm of the ascending aorta.

Desmoplastic nested spindle cell tumor of liver: report of four cases of a proposed new entity.

We describe a distinctive tumor of the liver in four children composed of nested spindled and epithelioid cells with extensive desmoplasia that we have termed "desmoplastic nested spindle cell tumor of the liver." All four patients were previously healthy. One patient had a presumptive diagnosis of hepatic hemangioma 11 years prior to presentation. Grossly, the tumors were well circumscribed, lobular white masses, ranging from 2.8 to 15 cm in diameter. These tumors were characterized by the presence of cohesive nests of plump, bland spindle cells arranged in short fascicles with an accompanying desmoplastic stroma. Epithelioid areas ranging from palisading epithelioid cells at the periphery of some nests to pseudoglandular and polygonal cells with intercellular bridges were invariably present. Mitotic activity was low. Calcification and ossification were present. Non-neoplastic bile ducts and hepatic elements were seen both within and surrounding the tumor cell nests. Each tumor displayed cytoplasmic reactivity for vimentin, pan-cytokeratin, CD57, and nuclear staining for WT1. Neuroendocrine markers were negative. Ultrastructurally, the tumor cells showed focally well-developed cell junctions, basal lamina, and few cytoplasmic organelles. All tumors were confined to the liver and were resected without complication. Two patients received postoperative adjuvant therapy for presumed hepatoblastoma. The patients are doing well without recurrence at 7.5 years, 7 years, 5 years, and 8 months post-surgery. The morphologic appearance and immunohistochemical profile of these lesions are unique in our experience and represent a new category of pediatric liver tumor.

EWS-ATF1 fusion transcripts in gastrointestinal tumors previously diagnosed as malignant melanoma.

BACKGROUND: Clear cell sarcoma (CCS) is classically a deep soft tissue tumor associated with tendons or aponeuroses, although cases of primary CCS of the gastrointestinal (GI) tract have recently been reported. Because it is difficult to distinguish CCS from metastatic melanoma based on morphology, immunohistochemical profile, and ultrastructural features, it is possible that some GI tumors diagnosed as metastatic melanoma actually represent primary GI CCS. Because the EWS-ATF1 fusion transcript and the associated t(12;22)(q13;q12) translocation occur in CCS but not cutaneous melanoma, we investigated the use of molecular-based testing for discriminating CCS from metastatic melanoma (MM) in GI tumors. METHODS: Patients with GI tumors diagnosed as MM were identified from departmental files. The tumors were tested for the EWS-ATF1 fusion transcript by RT-PCR and for t(12;22)(q13;q12) by fluorescence in situ hybridization. RESULTS: Detailed review of medical records revealed that 16 (80%) of the 20 had a documented history of cutaneous melanoma. Two cases (10%) harbored the EWS-ATF1 fusion transcript, and fluorescence in situ hybridization confirmed the presence of t(12;22) in both cases. Of the 2 positive tumors, 1 developed in a patient who had no history of cutaneous melanoma, and the other developed in a patient with a remote history of vulvar melanoma. CONCLUSION: Based on molecular genetic findings, a subset of GI tumors diagnosed as MM by routine histopathologic evaluation represents CCS.

Expression of Sirt1 and FoxP3 in classical Hodgkin lymphoma and tumor infiltrating lymphocytes: Implications for immune dysregulation, prognosis and potential therapeutic targeting.

BACKGROUND: Hodgkin Reed-Sternberg (HRS) cells may promote differentiation of CD4+ naïve T cells toward both FoxP3+ T regulatory (Treg) cells and TIA-1+ cytotoxic T lymphocytes (CTL). Previous studies suggest that an overabundance of cytotoxic TIA-1+ cells in relation to FoxP3+ T reg cells portends unfavorable outcomes in classical Hodgkin lymphoma (cHL), raising the possibility that its pathogenesis may be related to immune dysregulation. Sirt1 deacetylates FoxP3 and leads to decreased Treg functionality. Our objective was to compare Sirt1 and FoxP3 expressions in Hodgkin lymphoma infiltrating lymphocytes (HLIL) and confirm Sirt1 expression in HRS cells. DESIGN: Immunohistochemical staining of paraffin-embedded tissue with antibodies to Sirt1, FoxP3, TIA-1, and CD8 was performed. Expression of Sirt1 was assessed in both the HRS cells and in the HLILs in twenty-four cases. Adequate tissue was available in 13 cHL cases to permit the enumeration of FoxP3, TIA-1 and CD8 by giving their percent staining of HLILs. RESULTS: In HLILs, nuclear expression of Sirt1 was 32-88% (mean 67%); FoxP3 expression was 9-40% (mean 23.9%); TIA-1 expression was 15-87% (mean 32%); and CD8 expression was 10-45% (mean = 31%). Sirt1 to FoxP3 ratio was 0.96-5.5 (mean 3.2). TIA-1 to FoxP3 ratio was 0.6-5.1 (mean 1.6). CD8 to FoxP3 ratio was 0.43-3.7 (mean 1.5). There was a difference of Sirt1 to FoxP3 ratios between remission and recurrence groups, being significantly higher in the recurrence group (P = 0.005). Sirt1 demonstrated high nuclear expression in the HRS cells of 21 out of 24 (88%) cases analyzed. CONCLUSION: The relative overexpression of Sirt1 to FoxP3 in HLILs may be considered possible targets for immune modulation. Histone deacetylase inhibitors may increase the efficacy of existing treatment regimens by downregulating SIRT1 gene mRNA/Sirt1 protein function and together with rapamycin could expand the T regulatory/FoxP3 population and functionality and improve prognosis for remission in cHL. Targeting Sirt1 in the HRS cells may facilitate their ability to promote naïve T cell differentiation toward Treg cells over CTL.

Serum albumin concentration and clinical assessments of nutritional status in hospitalized older people: different sides of different coins?

OBJECTIVES: Malnutrition is common in hospitalized older people, and some have advocated routine nutritional screening. Serum albumin and clinically based measures such as the Subjective Global Assessment (SGA) are two potential methods of assessing nutritional status in hospitalized older people. Although both measures are strongly associated with prognosis, it is not clear whether they measure similar or different clinical constructs. Our goal was to assess the degree of clinical concordance between these measures. DESIGN: Cross-sectional study. SETTING: The inpatient medical service of a university teaching hospital. PARTICIPANTS: Three hundred eleven older (aged > or =70) patients. MEASUREMENTS: We independently measured serum albumin and performed the SGA on 311 older medical patients (aged > or =70) shortly after hospital admission. The SGA classified patients as well nourished, moderately malnourished (generally 5% weight loss with mild examination findings), or severely malnourished (generally >10% weight loss with marked findings) based on findings from a directed history and examination. We compared the distribution of clinical rating in patients with differing albumin levels and examined diagnostic test characteristics of albumin as a predictor of malnutrition as diagnosed on clinical examination. RESULTS: The mean age of subjects was 79.9; 64% were women, 42% were African American. Discordance between albumin and the SGA was common. For example, 38% of patients with albumin levels of 4.0 g/dL or higher were at least moderately malnourished on the SGA, whereas 28% of patients with albumin levels lower than 3.0 g/dL were rated as well nourished. No choice of albumin level was associated with simultaneously acceptable sensitivity and specificity as a predictor of SGA ratings. The area under the receiver operating characteristic curve for albumin level as a predictor of SGA rating was 0.58, suggesting that the ability of either measure to predict the other measure is only marginally better than chance. CONCLUSIONS: Albumin levels and clinical assessments, two possible measures of nutritional status in hospitalized older people, are often discordant. To some extent, this reflects limitations in both measures as markers of nutritional status. However, it also demonstrates that, in this population, albumin and clinical assessments of nutritional status reflect fundamentally different clinical processes.

Bilateral ovarian capillary hemangioma with stromal luteinization and hyperandrogenism.

A 77-year-old female presented to the outpatient clinic with a six-month history of left lower quadrant abdominal fullness and pressure. Serum levels included free testosterone 3.8 pg/mL (normal 0-1.8 pg/mL) and testosterone 259 ng/dL (normal 3-41 ng/dL). Magnetic resonance imaging of the pelvis showed bilateral small ovarian cystic masses with marked, progressive enhancement, and restriction of diffusion. Laparoscopic bilateral salpingo-oophorectomy was performed and showed left and right ovarian hemorrhagic masses measuring 2.1 cm and 0.6 cm respectively. The histology showed benign vascular lesions composed of small capillary vessels with a rim of luteinized stromal cells. The luteinized cells were strongly positive for inhibin A. The endothelial cells were negative for estrogen receptor and progesterone receptor. To our knowledge, this is the first reported case of bilateral ovarian hemangioma with stromal luteinization and hyperandrogenism.

Clear cell sarcoma of kidney: morphoproteomic analysis reveals genomic correlates and therapeutic options.

We used the morphoproteomic approach to analyze clear cell sarcoma of kidney (CCSK), a rare pediatric renal tumor, for which the exact pathogenesis and reliable diagnostic markers remain inexplicable. The tumor, currently being treated with chemotherapy and radiation therapy before or after radical nephrectomy, has demonstrated improved survival rates after introduction of doxorubicin. Three cases of CCSK were studied. We attempted to decipher the possible pathological mechanisms involved in CCSK and to explore the therapeutic targets and plausible less-toxic chemotherapeutic agents. We propose that cyclin D1 may be a central molecule in the pathogenesis of CCSK, driven mainly by the sonic hedgehog and the nuclear factor-kappa B pathways and secondarily by the mammalian target of rapamycin complex mTORC2/PI3K/Akt pathway, heat shock protein 90, and possibly phospholipase D1. Inclusion of relatively less toxic but effective therapies in the form of statins, 13-cis retinoic acid, curcumin, and 17-AAG in the combinatorial treatment strategies, which can target the involved subcellular pathways, may be considered.

Morphoproteomics provides support for TGF-ß pathway signaling in the osteoclastogenesis and immune dysregulation of osteolytic Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) has a challenging and still unclear pathogenesis. A body of literature points to impaired maturation of the lesional dendritic cells, and to immune dysregulation in the form of increased FoxP3 cells. Various cytokine abnormalities such as expression of transforming growth factor (TGF)-ß have been reported, as well as abnormalities in lipid content in LCH cells. Morphoproteomic techniques were applied to identify the signal transduction pathways that could influence histogenesis and immune regulation in osteolytic LCH. Five pediatric cases of osteolytic LCH were examined, using antibodies against CD1a, S100, CD68, CD8, FoxP3, phosphorylated (p)-STAT3 (Tyr705), protein kinase C (PKC)-α, phospholipase (PL)D1, fatty acid synthase (FASN), and zinc finger protein, Gli2. Positive and negative controls were performed. A FoxP3(+)/CD8(+) cell ratio was calculated by counting the FoxP3+ and CD8+ cells in 10 high power fields for each case. There is induction of sonic hedgehog (SHH) mediators consistent with TGF-ß signaling pathway through Smad3-dependent activation of Gli2, findings supported by the plasmalemmal and cytoplasmic expression of PKC-α and PLD1, and nuclear expression of Gli2, in lesional cells. The FoxP3+/CD8+ cell ratio is increased, ranging from 1.7-7.94. There is moderate cytoplasmic expression of FASN in most of the Langerhans cells, a finding that supports previously published phospholipid abnormalities in LCH and is consistent with PKC-α/PLD1/TGF-ß signaling. With our study, we strongly suggest that the TGF-ß cell signaling pathway is a major player in the pathogenesis of LCH, leading to non-canonical induction of nuclear Gli2 expression, thereby contributing to osteoclastogenesis in LCH histiocytes. It could also cause a state of immune frustration in LCH, by inducing the transformation of CD4(+)CD25(-) cells into CD4(+)/FoxP3(+) cells. This coincides with the clinical evidence of a response to thalidomide in patients with osteolytic LCH, given its reported ability to reduce TGF-beta 1 and FoxP3 cells. Such TGF-ß signaling in osteoclastogenesis and immune dysregulation, and the presence of FASN in the majority of cells, have additional therapeutic implications for osteolytic LCH.