Keratoacanthoma: a distinct entity?

Keratoacanthoma (KA) are common but exceptional benign tumors, often appearing on sun-exposed areas of light skinned people and showing spontaneous resolution. The goal of this study was to review existing literature, to point out the etiological complexity of KA biology and to answer the controversial debate if or not KA is a distinct entity or a variant of squamous cell carcinoma (SCC). Relying on recent results, we highlight that KA is an individual lesion with a unique molecular signature caused by alterations in the TGFß signalling pathway. These recent findings will help to understand the nature of KA and to develop new reliable diagnostic tools, simplifying the discrimination of the histologically similar KA and SCC.

Desmoplastic nevus of chronically sun-damaged skin: an entity to be distinguished from desmoplastic melanoma.

Desmoplastic (sclerotic) nevus (DSN) can often be difficult to differentiate from desmoplastic melanoma (DM). This can be especially difficult when DSNs occur in a background of heavy solar elastosis. We have observed numerous examples of DSNs occurring in chronically sun-damaged (CSD) skin. In a subset of these cases, we have observed notable pleomorphism and nuclear atypia raising concern for the possibility of DM. In this study, we evaluated the clinical, histopathologic, and immunohistochemical findings in 23 cases of DSN occurring in CSD skin and compared them with 10 cases of DM. DSN on CSD skin is seen in adults (mean, 53.2 years) with a female predominance (70%) and upper (57%) and lower (17%) extremity anatomic locations. Most DSNs present as small flesh-colored macules or papules. Typical histologic features include symmetry, limited junctional growth, presence of a lentiginous component often with focal and limited pagetoid spread (extension across only a few rete ridges), and lack of deep extension. DSN and DM had a statistically significant difference in immunohistochemical staining for Melan-A and p75. Melan-A was positive in 18 of 20 DSNs and only 2 out of 10 DMs, whereas p75 was positive in all DMs (10/10) and was weakly positive in 11 of 20 DSN cases. We believe that our study offers some useful clinical, histologic, and immunohistochemical clues to help differentiate DSNs on CSD skin from DMs.

MITF positivity in atypical fibroxanthoma: a diagnostic pitfall.

Microphthalmia transcription factor (MITF) is an established melanocytic marker originally credited with a high degree of specificity. We report a series of 11 atypical fibroxanthoma (AFX) from 2 laboratories showing positive MITF staining. Although there are multiple case reports illustrating MITF staining in a range of tumors, aberrant staining in AFX has not been previously reported. Awareness of the possibility of MITF positivity in AFX is important to avoid a misdiagnosis of melanoma. We also report positive MITF staining in 2 nonneural granular cell tumors and discuss the overlap with the granular subtype of AFX.

A gene expression signature distinguishes normal tissues of sporadic and radiation-induced papillary thyroid carcinomas.

BACKGROUND: Papillary thyroid cancer (PTC) incidence increased dramatically in children after the Chernobyl accident, providing a unique opportunity to investigate the molecular features of radiation-induced thyroid cancer. In contrast to the previous studies that included age-related confounding factors, we investigated mRNA expression in PTC and in the normal contralateral tissues of patients exposed and non-exposed to the Chernobyl fallout, using age- and ethnicity-matched non-irradiated cohorts. METHODS: Forty-five patients were analysed by full-genome mRNA microarrays. Twenty-two patients have been exposed to the Chernobyl fallout; 23 others were age-matched and resident in the same regions of Ukraine, but were born after 1 March 1987, that is, were not exposed to ¹³¹I. RESULTS: A gene expression signature of 793 probes corresponding to 403 genes that permitted differentiation between normal tissues from patients exposed and from those who were not exposed to radiation was identified. The differences were confirmed by quantitative RT-PCR. Many deregulated pathways in the exposed normal tissues are related to cell proliferation. CONCLUSION: Our results suggest that a higher proliferation rate in normal thyroid could be related to radiation-induced cancer either as a predisposition or as a consequence of radiation. The signature allows the identification of radiation-induced thyroid cancers.

Postradiation cutaneous angiosarcoma after treatment of breast carcinoma is characterized by MYC amplification in contrast to atypical vascular lesions after radiotherapy and control cases: clinicopathological, immunohistochemical and molecular analysis of 66 cases.

Postradiation cutaneous vascular lesions after treatment of breast carcinoma comprise a heterogeneous group of benign, atypical, and malignant lesions and are best regarded as points along a morphological spectrum. We analyzed a series of cutaneous angiosarcomas after treatment of breast cancer in comparison with control cases and cases of atypical vascular lesions with special emphasis on the expression and amplification of MYC. The 66 cases were divided into control cases (5), cases in which a slight vascular proliferation was seen after radiotherapy of breast cancer (12), cases of atypical vascular lesions after radiotherapy (16), cases of postradiation cutaneous angiosarcomas (25), and cases of angiosarcomas of skin and soft tissues unrelated to radiotherapy (8). None of the control cases (2 M, 3 F, 20-76 years), of cases showing slight vascular proliferation, dermal fibrosis and inflammation after radiotherapy of breast cancer (12 F, 48-79 years), of cases of atypical vascular lesions after radiotherapy (16 F, 29-81 years), and of cases of angiosarcomas of skin and soft tissues unrelated to radiotherapy (3 M, 5 F, 25-92 years) showed an amplification of MYC by FISH analysis. In striking contrast, in all cases of postradiation cutaneous angiosarcomas (25 F, 46-95 years), MYC amplification was found by FISH analysis in a variable number of counted nuclei. Immunohistochemically, strong positive nuclear staining for MYC and prox-1 was seen in cases of postradiation cutaneous angiosarcoma, whereas control cases and cases of atypical vascular proliferation after radiotherapy were negative for MYC, and stained only focally positive for prox-1 in a number of cases. In conclusion, the presence of MYC amplification represents an important additional diagnostic tool in the distinction of postradiation cutaneous angiosarcomas from atypical vascular lesions after radiotherapy. Immunohistochemical stainings for MYC are useful for mapping of these lesions and for careful tumor margin control.

Pancreas-preserving segmental duodenectomy for gastrointestinal stromal tumor of the duodenum and splenectomy for splenic angiosarcoma.

BACKGROUND: Gastrointestinal stromal tumors are the most common mesenchymal tumors of the gastrointestinal tract and occur rarely in the duodenum. Splenic angiosarcoma is an aggressive neoplasm with an extremely poor prognosis. METHODS: We report a case of a 70-year-old man hospitalized for abdominal pain in the upper quadrants, dyspepsia and nausea, previously treated for Hodgkin lymphoma 30 years ago. Abdominal CT showed a solid nodular lesion in the third portion of the duodenum, the presence of retropancreatic, aortic and caval lymph nodes, and four nodular splenic masses. (111)In-octreotide scintigraphy revealed pathological tissue accumulation in the duodenal region, and in the retropancreatic, retroduodenal, aortic and caval lymph nodes, suggesting a nonfunctioning neuroendocrine peripancreatic tumor. RESULTS: At exploratory laparotomy, an exophytic soft tumor was found originating from the third portion of the duodenum. Pancreas-preserving duodenectomy with duodenojejunostomy, splenectomy and lymphnodectomy of retropancreatic aortic and caval lymph nodes were performed. Pathological evaluation and immunohistochemical studies showed the presence of a duodenal gastrointestinal stromal tumor with low mitotic activity and a well-differentiated angiosarcoma localized to the spleen and invading lymph nodes. CONCLUSIONS: We speculated that the angiosarcoma and duodenal gastrointestinal stromal tumors of this patient were due to the treatment of Hodgkin lymphoma with radiotherapy 30 years ago. Pancreas-preserving segmental duodenectomy can be used to treat non-malignant neoplasms of the duodenum and avoid extensive surgery. Splenectomy is the treatment of choice for localized angiosarcomas but a strict follow-up is mandatory because of the possibility of recurrence.

Characteristic gene expression in stromal cells of gastric cancers among atomic-bomb survivors.

To elucidate the mechanism of radiation-induced cancers, molecular analysis of cancers in atomic-bomb survivors is important. In our study, we developed a custom oligonucleotide array of 208 genes. We analyzed gene expression profiles of gastric cancers (GCs) from atomic-bomb survivors and identified 9 genes with significantly lower expression in GCs from exposed patients than in GCs from nonexposed patients. Among these 9 genes, expression of versican and osteonectin was investigated in greater detail using immunohistochemistry in 116 GCs from 64 exposed and 52 nonexposed patients who developed GC after the bombing. In the Stage I/II GCs, the clinicopathologic, phenotypic and proliferative characteristics of GCs from exposed and nonexposed patients did not differ significantly; however, versican and osteonectin were expressed at much lower levels in the area of tumor-associated stroma of exposed patients than in nonexposed patients (p = 0.026 and p = 0.024, respectively). These results suggest that the characteristics of tumor-associated stromal cells differ between GCs from exposed and nonexposed patients.

Sporadic and radiation-associated papillary thyroid cancers can be distinguished using routine immunohistochemistry.

We investigated protein abundance in order to differentiate radiation-associated papillary thyroid cancers (PTC) from other etiologies for e.g. forensic purposes. Proteins were extracted from frozen tissues originating from 91 sporadic PTCs and 86 post-Chernobyl PTCs. Proteins were separated gel-electrophoretically, gels were silver stained, spots scanned and their intensity quantified. After excision of spots from the gel and protein digestion, MALDI-TOF mass spectrometry was performed followed by correlation of these results to human proteins using appropriate software and database. After this screening approach, altogether 20 candidate proteins were selected and measured semiquantitatively (Remmele score) using immunohistochemistry. Logistic regression modeling was performed for discriminating the groups. NTRK1, metalloproteinases (MMP-1, MMP-9 and MMP-13) and Cathepsins (-W and -X) proved to be of highest significance for discriminating the groups irrespective of the regression model utilized. When considering age and gender, each of 3 proteins by itself made possible a complete separation of the groups otherwise a combination of 2 of the 5 proteins mentioned was needed. In conclusion, abundance of proteins known to be associated with a more aggressive tumor type (MMPs and Cathepsins) appeared increased in post-Chernobyl PTC compared to sporadic PTC, thus underlining the known aggressiveness of radiation-associated PTC. These proteins make it possible to completely distinguish post-Chernobyl from sporadic PTC using routine immunohistology.

Encapsulated anaplastic thyroid carcinoma transformed from follicular carcinoma: a case report.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is rare but is one of the most aggressive and lethal human malignancies. Cytologically, ATC has a variable morphologic appearance, including squamoid, giant, spindled and pleomorphic cells. The coexistence of ATC and differentiated or poorly differentiated thyroid carcinoma has been described and usually is diagnosed when the disease is locally advanced. CASE: We describe a case of surgically resectable, encapsulated, well-circumscribed ATC occurring in association with a better differentiated follicular carcinoma diagnosed by fine needle aspiration in a patient exposed to external ionizing radiation. CONCLUSION: Encapsulated variants of anaplastic carcinoma can be seen in association with lower grade thyroid carcinoma such as follicular carcinoma. Accurate diagnosis is dependent on adequate sampling.

Staged margin control techniques for surgical excision of lentigo maligna.

For melanoma in situ (MIS) arising in chronically photodamaged skin (a.k.a. lentigo maligna, LM), the preferred treatment remains surgical excision. Yet, the standard 5-mm margins of excision recommended for other subtypes of MIS have proven insufficient for LM, due to the its indistinct borders. In this report, authors review specialized surgical techniques for the treatment of LM that focus on meticulous assessment of peripheral margins prior to closure (staged margin control) conducted with analysis of either frozen or permanent histologic sections. Techniques utilizing permanent sections include variations of the ''square'', ''perimeter'', and ''contoured'' excisions, and recurrence rates with these techniques are reportedly low based on short-term follow-up. Similarly, Mohs micrographic surgery (MMS) has been reported to be effective in LM, with recurrence rates generally less than 1% over three-five years of follow-up. In order to simplify margin assessment for MMS, many investigators have begun to rely on intraoperative immunohistochemistry (IHC) to identify melanocytes in frozen sections, and MART-1 is surrently the preferred immunostain for this purpose. Other methods of IHC are currently under investigation. Regardless, surgical methods that employ this degree of margin assessment offer superior cure rates compared to standard excision, and should be seriously considered when encountering patients with LM. Total peripheral margin assessment using staged excisions and analysis of permanent sections appears to be a simple and effective alternative to MMS, especially for institutions that prefer examination of permanent sections to frozen sections.

Analysis of the relationship between p53 immunohistochemical expression and risk factors for lung cancer, with special emphasis on residential radon exposure.

BACKGROUND: Indoor radon exposure has been postulated as the second risk factor of lung cancer after tobacco. The objective of this work is to analyze if there exists any effect on p53 immunohistochemical expression mainly due to radon exposure and other risk factors for lung cancer. PATIENTS AND METHODS: The tumor samples of a case series of 163 lung cancer cases were analyzed to know the p53 staining. The staining was classified into four categories from no staining to intense staining (>60%). This staining was correlated with radon exposure, tobacco consumption, having worked in risk occupations for lung cancer and alcohol consumption. RESULTS: Only 72 samples could be analyzed for immunohistochemistry and some of these samples were sequenced from exons 4-8. No association was observed for staining intensity and radon exposure and also for tobacco and occupation. A slight association with a more intense staining was observed for high alcohol intake. In the four samples with a staining >60% that could be sequenced from exons 4 to 8, no mutation was observed in the p53 gene. CONCLUSION: There is no association between radon exposure and p53 expression, indicating that maybe the effect of radon is not mediated through p53 alterations.

High relative biologic effectiveness of carbon ion radiation on induction of rat mammary carcinoma and its lack of H-ras and Tp53 mutations.

PURPOSE: The high relative biologic effectiveness (RBE) of high-linear energy transfer (LET) heavy-ion radiation has enabled powerful radiotherapy. The potential risk of later onset of secondary cancers, however, has not been adequately studied. We undertook the present study to clarify the RBE of therapeutic carbon ion radiation and molecular changes that occur in the rat mammary cancer model. METHODS AND MATERIALS: We observed 7-8-week-old rats (ACI, F344, Wistar, and Sprague-Dawley) until 1 year of age after irradiation (0.05-2 Gy) with either 290 MeV/u carbon ions with a spread out Bragg peak (LET 40-90 keV/mum) generated from the Heavy-Ion Medical Accelerator in Chiba or (137)Cs gamma-rays. RESULTS: Carbon ions significantly induced mammary carcinomas in Sprague-Dawley rats but less so in other strains. The dose-effect relationship for carcinoma incidence in the Sprague-Dawley rats was concave downward, providing an RBE of 2 at a typical therapeutic dose per fraction. In contrast, approximately 10 should be considered for radiation protection at low doses. Immunohistochemically, 14 of 18 carcinomas were positive for estrogen receptor alpha. All carcinomas examined were free of common H-ras and Tp53 mutations. Importantly, lung metastasis (7%) was characteristic of carbon ion-irradiated rats. CONCLUSIONS: We found clear genetic variability in the susceptibility to carbon ion-induced mammary carcinomas. The high RBE for carbon ion radiation further supports the importance of precise dose localization in radiotherapy. Common point mutations in H-ras and Tp53 were not involved in carbon ion induction of rat mammary carcinomas.

Cross-resistance to cisplatin in cells resistant to photofrin-mediated photodynamic therapy.

This study shows that a Photofrin-induced photodynamic therapy-resistant variant (RIF-8A) of a radiation-induced fibrosarcoma-1 cell line (RIF-1) is cross-resistant to cis-diamminedichloroplatinum(II) (cisplatin). This is the first study to show cross-resistance to cisplatin in photodynamic therapy-resistant variants in vitro. Resistance does not appear to be the result of elevated glutathione levels since neither the resistant variant (RIF-8A) nor the parental line (RIF-1) varied in total glutathione levels. However, cisplatin-DNA adduct levels differed significantly between the two cell types. Immediately following a 1-h exposure to cisplatin (50 microM), RIF-1 cells contained 44.6 +/- 2.0 (SEM) pg platinum/micrograms DNA while RIF-8A cells contained 24.8 +/- 6.3 pg platinum/micrograms DNA. In addition, the resistant variant had decreased plasma and mitochondrial membrane potentials. The plasma and mitochondrial membranes of the resistant variant accumulated 3- and 3.6-fold less rhodamine 123, respectively. The difference in rhodamine 123 accumulation could not be attributed to elevated P-glycoprotein expression because both the parental line and the variant contained similar amounts of P-glycoprotein. In conclusion, alterations in the plasma and/or mitochondrial membrane potentials may provide cells with a survival advantage when challenged with either photodynamic therapy or cisplatin in vitro. This appears to be a novel mechanism of resistance.

A case of radiation-induced mucosal melanoma in an immunohistochemically S-100-negative patient.

We report a case of radiation-induced mucosal melanoma in a 41-year-old woman with a history of childhood rhabdomyosarcoma of the nasal cavity that had been treated with radiotherapy. During the workup for the melanoma, the patient was found to be negative for S-100 protein on immunostaining. While many melanotic markers for the histologic confirmation of melanoma exist, they can be negative in some cases, such as ours. To the best of our knowledge, only 1 case of radiation-induced melanoma has been previously reported in the English-language literature, and in that case the patient was S-100-positive. Although our case is rare, it suggests another possible long-term adverse effect of radiotherapy. We also describe the morphologies and histology associated with diagnosing melanoma in an S-100-negative patient.

Protein oxidation, UVA and human DNA repair.

Solar UVB is carcinogenic. Nucleotide excision repair (NER) counteracts the carcinogenicity of UVB by excising potentially mutagenic UVB-induced DNA lesions. Despite this capacity for DNA repair, non-melanoma skin cancers and apparently normal sun-exposed skin contain huge numbers of mutations that are mostly attributable to unrepaired UVB-induced DNA lesions. UVA is about 20-times more abundant than UVB in incident sunlight. It does cause some DNA damage but this does not fully account for its biological impact. The effects of solar UVA are mediated by its interactions with cellular photosensitizers that generate reactive oxygen species (ROS) and induce oxidative stress. The proteome is a significant target for damage by UVA-induced ROS. In cultured human cells, UVA-induced oxidation of DNA repair proteins inhibits DNA repair. This article addresses the possible role of oxidative stress and protein oxidation in determining DNA repair efficiency - with particular reference to NER and skin cancer risk.

CNS Masson Tumors: Frequent Association With Therapeutic Radiation.

Masson tumor (MT, papillary endothelial hyperplasia) is an exaggerated form of thrombus reorganization rarely occurring in the central nervous system (CNS), where it presents as a mass or hemorrhage in parenchyma, meninges, or venous sinuses. MT is subclassified as type 1 arising within a histologically normal vessel, type 2 associated with a ruptured vascular malformation, and extravascular. Limited reports of CNS MT after radiosurgery, or especially external radiation therapy, have emerged. We searched our databases for cases reported from 2008 to present. Nine cases were identified, 6 of which were associated with receipt of therapeutic radiation for known lesions, with intervals of 1 to 25+ years to MT development (4 neoplasms=external beam radiation; 1 neoplasm=external beam radiation+radiosurgery, 1 arteriovenous malformation=radiosurgery). MTs were coassociated with radiation-induced vascular malformations (1 cavernoma-like, 1 massive) only in 2 of 6 irradiated patients, whereas the other 4 had MTs only. The 3 MTs in nonirradiated patients were extravascular, with 1 spontaneously developing in a hemangioblastoma. Seven of 9 MTs were intracerebral, 1 was within the spinal cord, and 1 was subdural. Papillary MT architecture was best appreciated by CD31 or CD34 immunohistochemistry, although ERG verified the endothelial monolayer population. Most CNS MTs at our institution have arisen in patients who have received therapeutic cranial radiation, many of whom received only external beam radiation. Although MTs could conceivably represent early, severe phases in radiation-induced cavernoma development, most were not found coassociated with the latter. This study further extends our knowledge of types of radiation-induced CNS vascular abnormalities.