Malignant melanoma arising from a perianal fistula and harbouring a BRAF gene mutation: a case report

Could Oxidative Stress Play a Role in the Development and Clinical Management of Differentiated Thyroid Cancer?

Increased oxidative stress (OS) has been implicated as a relevant risk factor for cancer progression. Furthermore, patients diagnosed with differentiated thyroid cancer (DTC) have been characterized by an increased OS status. Therefore, assessing OS status could potentially be considered a useful tool in DTC clinical management. This measurement could be particularly valuable in personalizing treatment protocols and determining new potential medical targets to improve commonly used therapies. A literature review was conducted to gather new information on DTC clinical management, with a particular focus on evaluating the clinical utility of OS. These meta-analyses concentrate on novel approaches that employ the measurement of oxidative-antioxidant status, which could represent the most promising area for implementing clinical management.

Diffuse large B cell lymphoma within an anal fistula: a case report with an intriguing possible aetiology

Described is a case of diffuse large B cell lymphoma that presented within a typical fistula tract, possibly secondary to oxidative stress within the fistula tract itself and consequent malignant change rather than a fistula as a consequence of necrosis in a lymphoma. If so it would be unique in the world literature. A 42-year-old fitness instructor presented with a typical appearing left lateral anal fistula. Biopsy of the fistulous tract revealed B cell lymphoma, graded 1E. Although chemotherapy cured the lymphoma, surgical treatment by ligation of the inter-sphincteric fistula tract was required to heal the fistula. At 3-year follow-up, there has been no recurrence of the lymphoma or the fistula. Neoplasia arising secondary to oxidative stress within an anal fistula is a well-established phenomenon. Early diagnosis of rare conditions associated with anal fistula can only be accomplished by routine biopsy of every fistula tract.

Oxidative stress in thyroid carcinomas: biological and clinical significance

At physiological concentrations, reactive oxygen species (ROS), including superoxide anions and H2O2, are considered as second messengers that play key roles in cellular functions, such as proliferation, gene expression, host defence and hormone synthesis. However, when they are at supraphysiological levels, ROS are considered potent DNA-damaging agents. Their increase induces oxidative stress, which can initiate and maintain genomic instability. The thyroid gland represents a good model for studying the impact of oxidative stress on genomic instability. Indeed, one particularity of this organ is that follicular thyroid cells synthesise thyroid hormones through a complex mechanism that requires H2O2. Because of their detection in thyroid adenomas and in early cell transformation, both oxidative stress and DNA damage are believed to be neoplasia-preceding events in thyroid cells. Oxidative DNA damage is, in addition, detected in the advanced stages of thyroid cancer, suggesting that oxidative lesions of DNA also contribute to the maintenance of genomic instability during the subsequent phases of tumourigenesis. Finally, ionizing radiation and the mutation of oncogenes, such as RAS and BRAF, play a key role in thyroid carcinogenesis through separate and unique mechanisms: they upregulate the expression of two distinct 'professional' ROS-generating systems, the NADPH oxidases DUOX1 and NOX4, which cause DNA damage that may promote chromosomal instability, tumourigenesis and dedifferentiation.

Identification of recurrent mutational events in anorectal melanoma

Anorectal melanoma is a rare disease that carries a poor prognosis. To date, limited genetic analyses confirmed KIT mutations as a recurrent genetic event similar to other mucosal melanomas, occurring in up to 30% of anorectal melanomas. Importantly, a subset of tumors harboring activating KIT mutations have been found to respond to c-Kit inhibitor-based therapy, with improved patient survival at advanced tumor stages. We performed comprehensive targeted exon sequencing analysis of 467 cancer-related genes in a larger series of 15 anorectal melanomas, focusing on potentially actionable variants based on gain- and loss-of-function mutations. We report the identification of oncogenic driver events in the majority (93%) of anorectal melanomas. These included variants in canonical MAPK pathway effectors rarely observed in cutaneous melanomas (including an HRAS mutation, as well as a BRAF mutation resulting in duplication of threonine 599), and recurrent mutations in the tumor suppressor NF1 in 20% of cases, which represented the second-most frequently mutated gene after KIT in our series. Furthermore, we identify SF3B1 mutations as a recurrent genetic event in mucosal melanomas. Our findings provide an insight into the genetic diversity of anorectal melanomas, and suggest significant potential for alternative targeted therapeutics in addition to c-Kit inhibitors for this melanoma subtype.

Assessment of Melanocyte Density in Anorectal Mucosa for the Evaluation of Surgical Margins in Primary Anorectal Melanoma

OBJECTIVES

Accurate histopathologic evaluation of surgical resection margins for anorectal melanoma (AM) is diagnostically challenging but essential to clinical management. We studied intraepithelial melanocyte density and growth pattern in anorectal mucosa and BRAF V600E mutation status in AM compared to controls.

METHODS

Histomorphology and melanocytic immunostains, microphthalmia transcription factor (MITF) and human melanoma black 45 (HMB45), were evaluated. Utility of VE1 immunostaining for determination of BRAF V600E mutation status was studied.

RESULTS

Immunostains aid in the distinction between "trailing" melanoma in situ (MIS) and benign melanocyte hyperplasia (BMH), by facilitating assessment of melanocyte density, and evaluation of nuclear atypia and growth pattern. While respective melanocyte densities overlapped, "trailing" MIS could be distinguished by melanocyte nuclear atypia and near confluent growth, compared to the banal cytology and scattered growth of BMH.

CONCLUSIONS

In the histopathologic assessment of AM resections, MITF and HMB45 immunostains aid in distinguishing between "trailing" MIS and BMH, by highlighting melanocyte density, nuclear atypia, and growth pattern, with the latter two being reliable features. VE1 showed nonspecific immunopositivity in anorectal glandular epithelium, a potential diagnostic pitfall when assessing BRAF mutation status.

Perianal melanoma with a BRAF gene mutation in a young Portuguese Roma native

A case of a young man diagnosed with perianal nodular melanoma with a gene mutation, accompanied by regional and pulmonary metastases on initial presentation, and later on with hepatic and bone involvement, is presented. The patient underwent wide local excision but was unresponsive to dacarbazine. Targeted therapy with vemurafenib had shown clinical improvement for a 5-month duration until he showed signs of disease progression. Just after the shift of adjuvant therapy to ipilimumab, he was diagnosed with multiple cerebral metastases that eventually led to his demise 6 months after initiation of vemurafenib, having had a 12-month survival period from the time of initial melanoma diagnosis.

[Melanoma of the anal margin]

BACKGROUND

Primary anal mucosal melanoma is rare and is associated with a poor prognosis. The observation of a case of anal melanoma at a localized stage in a woman led us to analyze recent data from the literature on therapeutic alternatives.

PATIENTS AND METHODS

A 49-year-old woman presented with a pigmented swelling of the anal margin that had begun three months earlier. Complete local excision of the tumour was performed with the conservation of the anal sphincters. Histological examination revealed SSM mucosal melanoma. Abdominoperineal resection was finally performed because of tumoural invasion of the lateral margins. Staging assessment was normal. Half-yearly MRI monitoring of the pelvis was proposed and at nine months no relapse was seen.

DISCUSSION

The unusual and misleading symptoms often account for the late diagnosis and poor prognosis of anal melanoma. Treatment is not well defined: local excision with conservation of the anal sphincters is recommended as first-line therapy, but the surgical technique is controversial. Abdominoperineal resection is recommended if the surgical margins are invaded, in the case of local recurrence or if the tumour is inaccessible. The place of adjuvant therapies remains to be defined. More recently, the discovery of mutation in c-KIT mucosal melanoma has allowed the use of biotherapy. Our observation underscores the importance of early detection of anal melanoma by all practitioners concerned in view of its aggressiveness and we report the difficulties of therapeutic management in the absence of established guidelines.

Anal cancer - a review

Anal cancer accounts for only 1.5% of gastrointestinal malignancies but this disease has shown a steady increase in incidence particularly in HIV positive males. The understanding of pathophysiology and treatment of anal cancer has changed radically over last thirty years. Risk factors have been identified and organ preservation by chemoradiotherapy has become a standard. This article aims to review the clinical presentation, diagnostic evaluation, and treatment options for anal cancer in the light of current literature.

Total oxidant/antioxidant status in sera of patients with thyroid cancers

Oxidative stress is considered to be involved in the pathophysiology of all cancers. In order to evaluate the total oxidant/antioxidant status in patients with thyroid cancer and to investigate the relationship between oxidative stress parameters and serum thyroid profiles among thyroid cancer patients and various controls, we determined oxidative status including total antioxidant status (TAS) and total oxidant status (TOS) and calculation of oxidative stress index (OSI) in sera in 82 thyroid cancer patients, 56 benign thyroid disease patients, and 50 healthy controls. It was found that serum TAS levels were significantly lower in patients with thyroid cancer than in controls (P<0.001), while serum TOS levels and OSI values were significantly higher (both P<0.001) in the cancer patients. No significant correlations were observed between various oxidative stress markers and thyroid profiles in either the thyroid cancer patients or the controls. Receiver operating characteristic curve analysis demonstrated that OSI was the best indicator for distinguishing cancer patients from benign thyroid diseased or healthy controls, followed by TOS and TAS. Risk estimate statistics also indicated that TOS and/or OSI were good risk factors to discriminate patients with thyroid cancer from two controls. These findings suggested that oxidants are increased and antioxidants are decreased in patients with thyroid cancer. OSI may be a more useful oxidative stress biomarker than TAS and TOS for monitoring the clinical status of thyroid cancer patients.