Melanocytes in the anal canal epithelium

Melanocytic nevus of the anal canal and granular cell tumor of the cecum: a case report and literature review of 2 coincidentally co-occurring neurocristopathies

Granular cell tumors are predominantly benign soft tissue tumors originating from Schwann cells, whereas melanocytic nevi are benign proliferations of melanocytes. We present the case of a patient with the presence of both entities located in the cecum and anal canal, respectively, constituting an extremely rare coincidental finding. A 43-year-old woman was evaluated by colonoscopy for iron-deficiency microcytic anemia that had lasted for 1 year. Colonoscopy demonstrated a macular lesion of 0.3 cm with a melanocytic appearance in the anal canal; at the cecum level, a subepithelial, yellowish, and partially mobile firm nodular lesion measuring 1.3 cm was observed. A histopathological study showed a melanocytic nevus in the anal canal and a granular cell tumor in the cecum. This is the first reported case of a patient with the extremely rare coincidental-incidental finding of these 2 entities at the same time.

Anal and Perianal Preneoplastic Lesions

Anal cancer, mainly squamous cell carcinoma, is rare but increasing in prevalence, as is its precursor lesion, anal squamous dysplasia. They are both strongly associated with human papillomavirus infection. The 2-tiered Lower Anogenital Squamous Terminology classification, low-grade SIL and high-grade SIL, is preferred to the 3-tiered anal intraepithelial neoplasia classification because of better interobserver agreement and clearer management implications. Immunohistochemistry with p16 is helpful to corroborate the diagnosis of squamous dysplasia. Similarly, immunohistochemistry is helpful to differentiate primary Paget disease from secondary Paget disease, which is usually due to anal squamous mucosal/epidermal involvement by primary rectal adenocarcinoma.

Proceedings from the Melanoma Research Foundation Mucosal Melanoma Meeting (December 16, 2022, New York, USA)

Mucosal melanoma remains a rare cancer with high mortality and a paucity of therapeutic options. This is due in significant part to its low incidence leading to limited patient access to expert care and downstream clinical/basic science data for research interrogation. Clinical challenges such as delayed and at times inaccurate diagnoses, and lack of consensus tumor staging have added to the suboptimal outcomes for these patients. Clinical trials, while promising, have been difficult to activate and accrue. While individual institutions and investigators have attempted to seek solutions to such problems, international, national, and local partnership may provide the keys to more efficient and innovative paths forward. Furthermore, a mucosal melanoma coalition would provide a potential network for patients and caregivers to seek expert opinion and advice. The Melanoma Research Foundation Mucosal Melanoma Meeting (December 16, 2022, New York, USA) highlighted the current clinical challenges faced by patients, providers, and scientists, identified current and future clinical trial investigations in this rare disease space, and aimed to increase national and international collaboration among the mucosal melanoma community in an effort to improve patient outcomes. The included proceedings highlight the clinical challenges of mucosal melanoma, global clinical trial experience, basic science advances in mucosal melanoma, and future directions, including the creation of shared rare tumor registries and enhanced collaborations.

Incidence and survival of patients with primary gastrointestinal melanoma: a population-based study

BACKGROUND

Primary gastrointestinal melanoma (PGIM) has received more attention because of its inferior prognosis. Less is known about the incidence and survival rate of PGIM.

METHODS

PGIM data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The incidence was estimated by age, sex, race, and primary site. Trends in incidence were described as annual percent change (APC). Cancer-specific survival (CSS) and overall survival (OS) rates were estimated and compared using log-rank tests. Cox regression analyses were performed to identify independent prognostic factors.

RESULTS

The overall incidence of PGIM was 0.360/1,000,000 with a significant upward trend (APC = 1.77%; 95% CI 0.89%-2.67%, p < 0.001) from 1975 to 2016. Most PGIM occurred in the large intestine (0.127/1,000,000) and anorectum (0.182/1,000,000), and both incidences were almost 10 times higher than those of other sites, including the esophagus, stomach, and small intestine. The median survival time was 16 months (IQR, 7-47 months) for CSS and 15 months (IQR, 6-37 months) for OS, and the 3-year CSS and OS rates were 29.5% and 25.4%, respectively. Older age, advanced stage, absence of surgery, and melanoma in the stomach were the independent risk indicators of survival and associated with worse CSS and OS.

CONCLUSION

The incidence of PGIM has been increasing over the past decades and the prognosis is poor. Thus, further studies are warranted to improve the survival, and more attention should be paid to the patients that are elderly, patients with advanced stage, and patients with melanoma in the stomach.

Management of Noncutaneous Melanomas

Noncutaneous melanomas are rare subtypes of melanoma with high rates of metastatic disease and poor overall survival. One-third to one-half of cases are amelanotic, which may contribute to a delay in diagnosis. Immunohistochemistry staining with typical melanoma markers helps confirm the diagnosis. There is no standard staging system across mucosal melanomas. Elective nodal dissection is not recommended and there is a paucity of data to support use of sentinel lymph node biopsy. Mutational analysis should be routinely performed. Systemic therapy options include targeted inhibitors, immunotherapy, and cytotoxic chemotherapy, although further studies are needed to confirm their efficacy.

Primary gastric melanoma in a young woman: A case report

BACKGROUND

Most melanomas identified in the stomach are metastatic. The primary gastric melanoma (PGM) is extremely rare. As such, clinical reports of PGM are scarce in the literature, lending to the challenge of diagnosis and treatment.

CASE SUMMARY

A 31-year-old woman presented with a 1-mo history of dysphagia but no symptoms of abdominal pain, abdominal distension, nausea, vomiting, hematemesis, or melena. The patient reported an unintentional weight loss of 6 kg within that time. History-taking revealed no previous medical conditions or surgical events. Abdominal computed tomography at a local hospital had suggested gastric tumor. Endoscopic examination in our hospital found a large, irregular, black mass. Subsequent laparoscopic exploration found the tumor on the side of the stomach fundus penetrating through the serosa, and enlarged lymph nodes (groups 1, 3, 7, and 9) fused into a mass, surrounding the peripheral artery and inseparable. Postoperative immunohistochemistry suggested gastric malignant melanoma. Positron emission tomography-computed tomography confirmed PGM. Treatment with programmed cell death protein 1 antagonist (toripalimab) plus chemotherapy (paclitaxel) was initiated but discontinued upon tumor bleeding. At the last telephone follow-up, the patient reported poor general condition but was alive.

CONCLUSION

Although unresolved and ongoing, this rare case of PGM expands the overall knowledge about this rare tumor’s diagnosis and management.

Human tumor genomics and zebrafish modeling identify SPRED1 loss as a driver of mucosal melanoma

Melanomas originating from mucosal surfaces have low mutation burden, genomic instability, and poor prognosis. To identify potential driver genes, we sequenced hundreds of cancer-related genes in 43 human mucosal melanomas, cataloging point mutations, amplifications, and deletions. The SPRED1 gene, which encodes a negative regulator of mitogen-activated protein kinase (MAPK) signaling, was inactivated in 37% of the tumors. Four distinct genotypes were associated with SPRED1 loss. Using a rapid, tissue-specific CRISPR technique to model these genotypes in zebrafish, we found that SPRED1 functions as a tumor suppressor, particularly in the context of KIT mutations. SPRED1 knockdown caused MAPK activation, increased cell proliferation, and conferred resistance to drugs inhibiting KIT tyrosine kinase activity. These findings provide a rationale for MAPK inhibition in SPRED1-deficient melanomas and introduce a zebrafish modeling approach that can be used more generally to dissect genetic interactions in cancer.

Resection for anal melanoma: Is there an optimal approach?

BACKGROUND

Anal melanoma is a lethal disease, but its rarity makes understanding the behavior and effects of intervention challenging. Local resection and abdominal perineal resection are the proposed treatments for nonmetastatic disease. We hypothesize that there is no difference in overall survival between surgical therapies.

METHODS

The National Cancer Database (2004-2014) was queried for adults with a diagnosis of anal melanoma who underwent curative resection. Patients with metastatic disease were excluded. Patients were divided into 2 groups based on surgical approach (local resection versus abdominal perineal resection). Unadjusted and adjusted analyses were used to examine the association between surgical approach and R0 resection rate, short-term survival, and overall survival.

RESULTS

A total of 570 patients with anal melanoma who underwent resection were identified. The median age was 68 and 59% of patients were female. A total of 383 (67%) underwent local resection. Abdominal perineal resection was associated with higher rates of R0 resection rates (abdominal perineal resection 91% versus local resection 73%; P < .001). Overall 5-year survival for the entire cohort was 20%. There was no significant difference in 5-year overall survival (abdominal perineal resection 21% vs local resection 17%; P = .31). This persisted in a Cox proportional hazard multivariable model (odds ratio 0.84; 95% confidence interval 0.66-1.06; P = .15). Additionally, there was no improvement in overall survival for patients who underwent R0 resection (odds ratio 1.18; 95% confidence interval 0.90-1.56; P = .22).

CONCLUSION

Anal melanoma has a very poor prognosis, with only 1 of 5 patients alive at 5 years. Although local resection was associated with lower rates of R0 resection, there was no discernable difference in overall survival in both unadjusted and adjusted analysis.

Reasons for rarity of anal melanocytic naevi

In the last 16 years only seven definite cases of anal melanocytic naevi have been reported in the literature. We describe three new cases, none of which were suspected clinically and were incidentally diagnosed on histological examination of haemorrhoidectomy specimens. The infrequency of these special site flexural melanocytic lesions may be related to changes in the involutionary mechanisms of the anal melanocyte proliferation. However, other factors related to the low detection rates by clinicians and pathologists need also to be considered.

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.

Duodenal and gallbladder metastasis of regressive melanoma: a case report and review of the literature

BACKGROUND

Malignant melanoma involving the gastrointestinal (GI) tract may be primary or metastatic. Small bowel is the commonest site of GI metastases from cutaneous malignant melanoma, metastatic lesion in the gallbladder is extremely rare.

CASE PRESENTATION

This case report describes the presentation of metastatic melanoma in duodenum and gallbladder. A 45-year-old man has presented melena with intermittent abdominal pain. On physical examination we found a small lesion between the fourth and fifth toes, associated with inguinal lymph node. An Abdominal ultrasound revealed diffuse duodenal thickening. Upper endoscopy was performed and discovered an ulcerative lesion in the second part of the duodenum. The biopsy with immunohistochemical stains was in favor of a duodenal location of melanoma. Computed tomography (CT) revealed many circumferential thickening of ileal loops associated with a nodular lesion in the anterior wall of the gallbladder. The patient was treated by palliative chemotherapy.

DISCUSSION

Malignant melanoma of the GI tract may be primary or secondary. The small bowel is the most affected, but it's rare in the gallbladder. The clinical presentation can mimic the other intestinal tumors, and the diagnosis is based on imaging; CT scan and GI endoscopy have a key role on the diagnosis, and the treatment depends on the location and the number of lesions.

CONCLUSIONS

Metastases of melanoma in the GI tract are uncommon, the diagnosis must be suspected in any patient with a history of melanoma with digestive signs.

Primary digestive melanoma in association with tubular adenoma: a case report illustrating the distinction from metastatic colonic melanoma

We report here an exceptional pattern of atypical lentiginous melanocytic proliferation within an adenoma, leading to focal lamina propria infiltration and pulmonary metastasis, which was considered as primary colonic mucosal melanoma (MM) in a Caucasian patient. Such case illustrates the diagnosis criteria required to differentiate primary MM from colonic metastasis of melanoma, including the absence of past history of other primary melanoma, a unique colonic and abdominal lesion with predominant features of in situ lentiginous MM and a very focal and unique invasive area without other digestive tract or abdominal localization. This tumor displayed a KIT exon 11 mutation leading to a unique combination of p.I571M and p.D572G deleterious amino acid changes. Such pattern also favors the diagnosis as KIT appears as a master oncogenic player in MM oncogenesis.

Intestinal obstruction due to primary intestinal melanoma in a patient with a history of rectal cancer resectioning: A case report

The vast majority of the cases of intestinal melanomas are metastatic lesions, originating from an occult primary cutaneous or ocular lesion, whereas primary small intestinal melanomas are extremely rare. This is a rare case of primary small intestinal malignant melanoma with intestinal obstruction in a patient with a prior history of rectal cancer resection. The patient was admitted for abdominal pain and obstipation. Following an overall inspection, the patient was subjected to surgical treatment and a small intestinal tumor was removed. The histopathological examination of the lesion revealed a diffuse neoplastic infiltration involving the entire thickness of the intestinal mucosa. The neoplastic cells exhibited marked atypia, pleomorphism and immunoreactivity to S-100, anti-melanoma antibody (HMB-45) and melanocyte/melanoma tumor antigen (Melan-A). The diagnosis of primary small intestinal melanoma was confirmed. The patient underwent an uneventful postoperative recovery and was administered adjuvant therapy. At the 3-month, 6-month and 1-year follow-up, the patient remained alive, with no signs of tumor metastasis and/or recurrence. In this case, the patient was repetitively assessed by abdominal computed tomography (CT) and plain film, confirming that the obstruction was caused by small intestinal melanoma. There was no association between the rectal cancer history and the melanoma. A definitive diagnosis requires detailed clinical, histopathological and immunohistochemical analyses.

Malignant melanoma of the ileo-anal pouch anastomosis after restorative proctocolectomy for ulcerative colitis: report of a case

A 62 year-old patient with therapy-refractory pouchitis after proctocolectomy for ulcerative colitis was admitted with hematochezia and abdominal discomfort. A malignant melanoma (MM) was found after repeated biopsies of the pouch. Complete staging revealed no evidence for distant metastases and the patient underwent abdominoperineal pouch resection. Six weeks later, the patient was readmitted because of severe general deterioration and diffuse metastatic spread to the liver was found. The patient died of hepatorenal syndrome shortly thereafter.

Patients with inflammatory bowel disease are at increased risk of developing cancer, including rarities such as MM. Our experience stresses the importance of repeated biopsies in therapy-refractory pouchitis.

Primary anorectal melanoma: an update

The anorectum is a rare anatomic location for primary melanoma. Mucosal melanoma is a distinct biological and clinical entity from the more common cutaneous melanoma. It portrays worse prognosis than cutaneous melanoma, with distant metastases being the overwhelming cause of morbidity and mortality. Surgery is the treatment of choice, but significant controversy exists over the extent of surgical resection. We present an update on the state of the art of anorectal mucosal melanoma. To illustrate the multimodality approach to anorectal melanoma, we present a typical patient.

Anorectal malignant melanomas: experience of Uludag University

Anorectal melanomas represent a group of mucosal melanomas with unknown etiology and poor prognosis. The lesions can be misdiagnosed as hemorrhoids during clinical examination. We reviewed the morphological and clinical features of 14 anorectal melanomas, and discuss the treatment modalities of this entity. Fourteen patients who were diagnosed with anorectal malignant melanoma between 1997 and 2004 were evaluated with regard to age, sex, size, morphology, lymph node or distant metastasis, treatment modality and survival. Eight patients were female and six were male, and their mean age was 58 years. The size of melanoma ranged from 3 cm to 8 cm. Pathological evaluation revealed epithelioid and spindle cell type tumor in seven and two patients, respectively, whereas, in the remaining seven patients, the tumor was composed of both types. Pigmentation was apparent in all tumors. There was lymph node metastasis in 11 patients and distant metastasis in all patients. Eleven patients underwent abdominoperineal resection and three were treated by local excision. Mean survival was 8.7 months. Prognosis of anorectal melanoma remains poor. Awareness of the diverse clinicopathological features of these lesions, both on the part of the clinicians and pathologists, is crucial for their early detection and proper treatment.

An update on tumors of the anal canal

CONTEXT

The anal canal possesses complex anatomy and histology and gives rise to a variety of tumor types. Challenging issues remain with regard to both the pathologic diagnosis and the clinical management of these tumors.

OBJECTIVES

To provide an updated overview of the histogenesis, clinical and pathologic characteristics, diagnostic terminology, and relevant clinical management of the various types of anal canal tumors.

DATA SOURCES

Recent literature on clinical and pathologic characteristics of anal canal tumors.

CONCLUSIONS

Although most anal canal tumors are of squamous lineage, a complex variety of other tumors also occurs. Recognition of such diverse tumor entities will allow accurate pathologic diagnosis and most optimal clinical management.

Primary ano-rectal malignant melanomas within a population-based national patient series in Sweden during 40 years

PURPOSE

To analyze 251 patients (101 males and 150 females) diagnosed with ano-rectal malignant melanoma (ARMM) reported to the Swedish National Cancer Registry during 1960-1999.

METHODS

Incidence, gender and age profiles, primary anatomical sites and density of the melanomas along with geographic distribution, and prognosis were investigated.

RESULTS

The age-standardized incidence of ARMM was significantly higher for females (1.0 per 10(6) females) than for males (0.7 per 10(6) males) throughout the 40-year-period. The incidence increased with age peaking at 75-84 years in both genders. 54% of the tumours were primary in the anal canal, 24% engaged the whole ano-rectal unit and 10% were located at the anal verge (11% unknown primary site). Although ARMM were rare in absolute numbers, their density (number of tumours/square unit) was higher than that of cutaneous malignant melanomas (CMM) on average. No linkage between the geographic distribution of ARMM and population density was found. The prognosis was very poor albeit with a significant gender difference with a five-year survival rate of 10.6% for males and 15.7% for females. The survival rates for both genders improved during the 40-year-period but significantly more for females than males.

CONCLUSION

The reason(s) for the difference in incidence and prognosis according to gender is unknown. The majority of ARMM emerged primary in the anal canal and a primary location exclusively in the colonic mucosa of the rectum is questionable. The higher density of ARMM as compared to the average density of CMM tallies with the result of our previous studies on vulvar melanoma and might be instrumental in exploring non-UV light associated factors in melanoma genesis. The concentration of patients with anal squamous cell carcinoma to population-dense urban areas, as previously reported, was not found in cases of ARMM.

Primary malignant melanoma of the liver: A case report

Primary malignant melanoma of the liver is an exceedingly rare tumor. Only 12 cases have been reported in the worldwide literature. We present a case of isolated malignant melanoma of the liver occurring in a 36-year-old Chinese male patient. Comprehensive dermatologic and ophthalmologic examinations revealed no evidence of a cutaneous or ocular primary lesion. Other lesions in brain, respiratory tract, lung, gastrointestinal tract and anus, were not demonstrated by serial position emission tomography (PET). Microscopic examination of the resected specimen revealed a malignant melanoma, which was confirmed by immunohistochemical staining for HMB-45, S-100 protein, melanoma-pan and vimentin. Moreover, electron microscopy demonstrated melanosomes in tumor cell cytoplasm. Our case shows that primary malignant melanoma may occur in the liver and should be considered when the histopathological appearance is not typical for other hepatic neoplasm.

Extracutaneous malignant melanomas

Extracutaneous malignant melanomas are rare tumors with vexing clinical presentation and grim prognosis. Only 4%-5% of all primary melanomas do not arise from the skin. These tumors are almost uniformly fatal, even in 2006. Although a fairly good number of these lesions were reported in the literature, the lack of a side-by-side analysis of these studies has resulted in tentative conclusions that merely offer a first glimpse at the clinicopathologic diversity of these lesions. To remedy this issue, this article took an aim at presenting a literature review concerning extracutaneous malignant melanomas. It also reports several cases of extracutaneous melanomas, which I came across in my 15 years of surgical and molecular pathology practice. The study raises several notions. Extracutaneous malignant melanomas are rare but extremely aggressive lesions with a grim outcome. They include ocular, metastatic, anorectal, mucosal, nail beds, conjunctival, vaginal, urogenital, orbital, esophageal, and leptomeningial malignant melanomas. The development of these lesions lacks an association with sun damage, family history, or precursor nevi. These lesions cause considerable diagnostic consternation and their distinction from other types of tumors (such as undifferentiated carcinomas, high-grade sarcomas, and lymphomas) is critical both from a diagnostic and prognostic point of view. In the proper clinical, histological, and cytological context, immunopositivity for S100 protein, HMB45, and vimentin allows the distinction of these malignant melanomas from other histologically similar malignancies. To conclude, extracutaneous melanoma should be considered while undifferentiated neoplasms, especially those displaying prominent eosinophilic nucleoli, and the coexistence of epithelioid and spindle cells. Special staining and immunohistochemistry should be resorted to establish the diagnosis.

Defining the role of surgery for primary gastrointestinal tract melanoma

OBJECTIVE

The objective of the study was to determine the outcomes for primary gastrointestinal melanomas (PGIM).

MATERIAL AND METHODS

The Surveillance, Epidemiology, and End Results database (1973-2004) was queried.

RESULTS

Overall, 659 cases of PGIM were identified. The annual incidence of PGIM was approximately 0.47 cases per million in 2000. Overall median survival time was 17 months. Tumors were identified in the oral-nasopharynx (32.8%), anal canal (31.4%), rectum (22.2%), esophagus (5.9%), stomach (2.7%), small bowel (2.3%), gallbladder (1.4%), and large bowel (0.9%). Univariate analysis demonstrated age, tumor location, stage, surgery, and lymph node status were significant predictors of improved survival. MST has not been reached for tumors located in the large bowel, while tumors located in the stomach demonstrated the shortest median survival (5 months). Improvement in MST was observed for those patients undergoing surgical resection. The presence of lymph node involvement conferred a poorer prognosis. Multivariate analysis of the cohort identified that location, advanced tumor stage, failure to undertake surgical resection, positive lymph node status, and age were all independent predictors of poorer outcome.

CONCLUSION

PGIM occurs most often in the oral-nasopharynx and anal canal. Surgical extirpation is the only identifiable treatment modality that significantly improves survival.

Anal intraepithelial neoplasia and other neoplastic precursor lesions of the anal canal and perianal region

Anal cancer is rare and this helps to explain why anal pre-neoplastic conditions are poorly understood, especially with regard to their natural history and management. Anal intraepithelial neoplasia is closely linked to human papillomavirus infection and is particularly common in homosexuals and in immunosuppressed patients, especially those with HIV/AIDS. The high regression rates of low-grade anal intraepithelial neoplasia may simply reflect inconsistent pathologic reporting. Higher grades of anal intraepithelial neoplasia may remain static for long periods of time in immunocompetent patients, but those with HIV/AIDS show early and rapid malignant transformation. In general, most anal pre-neoplastic conditions are best diagnosed by biopsy and treated by surgical excision, although local recurrence is a problem. In anal Paget's disease, it is important to ascertain, at the time of diagnosis, whether it is due to a primary in-situ apocrine-type of neoplasia of the anus or if the disease is secondary to an invasive primary carcinoma of the rectum.

Poorly differentiated tumours of the anal canal: a diagnostic strategy for the surgical pathologist

Poorly differentiated malignancies affecting the anal canal are uncommon but pose diagnostic difficulties because of the wide range of normal cell types that may occur within a limited anatomical region. The range of lesions that may present as poorly differentiated tumours includes squamous cell carcinoma, adenocarcinoma, small and large cell neuroendocrine carcinoma, neuroendocrine carcinoma expressing epithelial cytokeratins and other patterns of mixed differentiation, undifferentiated carcinoma, malignant melanoma, lymphoma and secondary tumours. This review discusses the differential diagnosis of these neoplasms with the aid of short illustrative case studies.

Primary gastric melanoma: A case report

Melanoma accounts for 1-3 per cent of all malignant tumors. Except cutaneous, other less common melanomas include, among others, those in the GI tract. However, their primary or secondary nature is often difficult to establish. Referring to the stomach, scattered cases of primary melanomas have been reported in the literature.

We report a case of a man with an ulcerated sub-mucosal mass at the antrum of the stomach, manifested with dull upper abdominal pain, nausea, vomiting, fatigue and anemia. This lesion was histologically proved to be melanoma. A detailed clinical and laboratory investigation revealed no primary site elsewhere.

To our knowledge, very few cases of primary gastric melanoma have been reported. Our case is the fourth ever published and the first located at the antrum of the stomach. The debate upon the primitive nature of such lesions still persists. Thus, specific diagnostic criteria have been proposed.

Metastatic malignant melanoma of the gastrointestinal tract

Malignant melanoma is one of the most common malignancies to metastasize to the gastrointestinal (GI) tract. Metastases to the GI tract can present at the time of primary diagnosis or decades later as the first sign of recurrence. Symptoms may include abdominal pain, dysphagia, small bowel obstruction, hematemesis, and melena. We report 2 cases of malignant melanoma metastatic to the GI tract, followed by a review of the literature. The first case is a 72-year-old man who underwent resection of superficial spreading melanoma on his back 13 years previously who presented with dysphagia. A biopsy specimen of a mucosal fold in a gastric fundus noted during endoscopy was taken and revealed metastatic malignant melanoma, which was resected 1 month later. Three weeks later, the patient was found to have an ulcerated jejunal metastatic melanoma mass, which was also resected. The second case is a 63-year-old man with an ocular melanoma involving the chorold of the left eye that had been diagnosed 4 years previously, which had been excised several times, who presented with anorexia, dizziness, and fatigue. He was found to have cerebellar and stomach metastases. He underwent adjuvant radiation therapy, chemotherapy, and surgical resection of the gastric melanoma metastasis. In patients with a history of melanoma, a high index of suspicion for metastasis must be maintained if they present with seemingly unrelated symptoms. Diagnosis requires careful inspection of the mucosa for metastatic lesions and biopsy with special immunohistochemical stains. Management may include surgical resection, chemotherapy, immunotherapy, observation, or enrollment in clinical trials. Prognosis is poor, with a median survival of 4 to 6 months.

Unusual clinical course of metachronous melanomas of the upper digestive system

Melanoma of the gastrointestinal tract is a rare, highly malignant neoplasm of poor prognosis. This is description of an unusual case of surgically treated patient with two metachronous malignant melanomas of the stomach and the esophagus. The former lesion was located in the cardia and effectively treated with R0 total gastrectomy. The latter was recognized after 67 mo and appeared as irregular, flat, pigmented areas located in the mid esophagus. Subtotal esophagectomy via right-sided thoracotomy, laparotomy and left-sided cervicotomy was performed, but neoplastic cells were found in distal margin (R1). Fourteen months after esophagectomy multiple lung metastases were detected. Patient died 2 mo later.

Anorectal melanoma: report of three cases with extended follow-up

Primary anorectal melanoma is rare. There is controversy regarding the best surgical treatment because of its poor prognosis. Three cases with extended follow-up are reported in this article. A 53-year-old woman with rectal bleeding was diagnosed with a melanoma of the rectum and underwent an abdominoperineal resection. The patient died with distant metastases 8 months later. An 80-year-old woman with rectal bleeding was diagnosed with a melanoma of the rectum and underwent a transanal local excision. She remains alive 4 years later but with locally recurrent disease. A 78-year-old man with rectal bleeding was diagnosed with a melanoma of the rectum and underwent an abdominoperineal resection. He died with local and metastatic disease 25 months later. Recent trends favor local excision when technically feasible, although some patients may require an abdominoperineal resection of the rectum, especially for larger tumors.

Primary and metastatic diseases in malignant melanoma of the gastrointestinal tract

In this review, the gastrointestinal (GI) manifestations of malignant melanoma including primary mucosal melanoma of the GI tract and metastatic melanoma to the GI tract are discussed. Although malignant melanoma most commonly arises in the skin, primary melanomas can also arise from the mucosal epithelial lining of the gastrointestinal tract. The vast majority of gastrointestinal melanoma is metastatic from a cutaneous primary; however, there is evidence that melanoma can arise de novo from within certain areas of the gastrointestinal system. The sporadic nature and small numbers of patients reported in the literature with mucosal melanomas have prevented a good understanding of the pathogenesis, natural history, and optimal treatment of this uncommon presentation of melanoma.

Melanoma in the gastrointestinal tract

OBJECTIVE

This article focuses on the clinical, diagnostic, and therapeutic aspects of malignant melanoma metastases to the gastrointestinal (GI) tract. The subject of primary malignant melanoma arising from the GI tract is also discussed. Malignant melanoma is the most common tumor metastatic to the GI tract, and can present with fairly non-specific symptoms.

METHODS

Up to 60% of patients with melanoma are found to have metastases at autopsy. Frequent GI sites of invasion include the small bowel (50%), colon (31.3%), and anorectum (25%), seen in our institution over the past 9 yr. Malignant melanoma is a frequent source of metastases to the gastrointestinal (GI) tract.

RESULTS

Herein we report the case of a melanoma masquerading as a rectal polyp. We have also discovered 16 cases of melanoma metastases to the GI tract, at our institution, over the past 9 yr. The most frequent sites included small bowel (50%), colon (31.3%), and anorectum (25%).

CONCLUSION

Despite innocuous gastrointestinal symptoms, metastatic melanoma should be a diagnostic consideration in any patient with a history of melanoma.

Malignant melanoma of the mucous membranes: a review of 119 cases

BACKGROUND

Melanomas arising from the mucous membranes lining the respiratory, digestive, and genitourinary tracts are rare. Women are more commonly affected than are men, mainly because there is no male counterpart for vulvovaginal lesions. The mainstay of therapy is surgery, with little current use of adjuvant modalities in primary therapy. These lesions usually are advanced at initial presentation; consequently, the prognosis is poor, with 5-year survivals well below 50% in most series.

METHODS

One hundred and nineteen patients with primary mucosal melanoma were reviewed. They represented 1.1% of the 10,393 melanoma patients seen at Duke University between 1970 and 1995. All data were obtained from the patients' clinic charts and computerized databases.

RESULTS

There were 43 tumors arising from the head and neck region, 46 from the urogenital tract, and 30 from the anorectum. A female predominance was observed, with a female-to-male ratio of 2.7:1. All but five of the patients underwent resection with curative intent. Regional or distant metastases, or both, were encountered in 36 patients at the time of presentation. In patients with head and neck and urogenital tumors, local recurrences accounted for most of the treatment failures, whereas systemic recurrences were more common with tumors arising in the anorectum. The age and gender of the patient, anatomic site of origin of the tumor, clinical stage at initial presentation, and ulceration of the primary all clearly affected prognosis. Overall, the probabilities of being alive 1, 5, and 10 years after diagnosis were 80%, 29%, and 15%, respectively.

CONCLUSIONS

Widely accepted classification systems are needed so that results from separate institutions can be compared adequately. Multi-institutional trials could help in delineating standardized therapeutic protocols and in establishing the potential roles of emerging modalities in the treatment of this subtype of melanoma.

Considerações sobre o tratamento cirúrgico do melanoma maligno anorretal

São analisados os resultados do tratamento cirúrgico em cinco casos de melanoma maligno anorretal (MMAR). Um paciente encontrava-se no estádio clínico I, dois no estádio clínico II e dois no estádio III. Todos os pacientes foram operados, sendo quatro submetidos a excisão local do tumor, e um a amputação abdômino-perineal do reto. Este último sobreviveu por apenas sete meses, enquanto uma paciente, estádio clínico II e submetida apenas à excisão local, sobreviveu por 168 meses. Os autores questionam a validade do estadiamento clínico I (tumores localizados) como fator prognóstico, já que desconsidera o grau de penetração do tumor na parede anorretal. Sugerem ainda a realização de estudos multicêntricos, para que se possa estabelecer uma uniformidade terapêutica para o MMAR.

A case of multiple nevoid hypertrichosis

Nevoid hypertrichosis is an uncommon congenital disorder consisting of terminal hair growth in a localized distribution on flesh-colored skin; it is not associated with any other systemic abnormalities. A 21-year-old male patient had a circumscribed area of depigmented terminal hairs on his chest which had been present since 1 year of age. At the age of 18, similar lesions developed on his left shoulder and upper arm. The underlying skin was slightly hypopigmented, and no other systemic abnormalities were found. Histologic examination demonstrated terminal hair follicles in otherwise normal skin. The number of HMB 45 positive melanocytes was markedly decreased in the affected skin. This case of multiple nevoid hypertrichosis is reported with a review of previously reported cases.

Ultrastructural evidence of cell communication between epithelial dark cells and melanocytes in vestibular organs of the human inner ear

BACKGROUND

The possibility of interaction between epithelial dark cells and melanocytes in the mammalian inner ear has been pointed out because of their morphological and biochemical characteristics, although very few studies have dealt directly with communication between these two types of cells. We investigated the dark cell area of human vestibular organs in order to clarify the ultrastructural evidence for cell interaction between epithelial dark cells and melanocytes.

METHODS

All of the material was obtained from vestibular schwannoma operations. Paraffin sections were stained with hematoxylin and eosin (H&E) and by the Fontana-Masson technique. Other paraffin sections were also stained immunohistochemically for S-100 protein. Glutaraldehyde fixed specimens were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

Light microscopy revealed melanin pigment granules in the cytoplasm of epithelial dark cells. Melanocytes in the subepithelial layer stained positively for S-100 protein. The presence of intraepithelial melanocytes was confirmed by the presence of cell profiles with a large number of melanin pigment granules and S-100 protein in the cytoplasm. SEM showed that the dark cells had a pentagonal surface with microvilli on the apical surface edge. They had complicated structures at the basal portion of their cytoplasm. Melanocytes extending cytoplasmic processes to adjacent areas were observed under the dark cells. TEM showed that the dark cells were tightly linked by junctional complexes in the upper lateral portion of their cytoplasmic membrane and interdigitated by lateral infoldings. Compound melanosomes (phagosomes or secondary lysosomes) found in the cytoplasm of the dark cells contained poorly pigmented melanosomes with a periodic internal structure. Gap junctions were clearly showed between adjacent melanocytes in the subepithelial layer.

CONCLUSIONS

The characteristic substructures of dark cells and melanocytes suggested the presence of intimate cell interaction between these two types of cells in the vestibular organs of the human inner ear, although it is not clear at this stage whether such cell interaction is specific only for patients with vestibular schwannoma. Dark cells and melanocytes form a cell community that serves to maintain homeostasis in vestibular organs through communication in which cell information obtained by both dark cells and melanocytes serves to facilitate the system.

Malignant melanoma of the anorectal region

The charts of 15 patients with malignant melanoma of the anorectal region treated at Roswell Park Cancer Institute in the period 1975-1991 were reviewed. All the lesions except one developed at the pectinate line, in the area of transitional mucosa. Two of the patients at the time of initial presentation had distant metastases. Of the remaining 13, 8 were treated with abdominoperineal resection (APR) and 5 with local excision (LE). The incidence of local recurrence was 50% in the LE group and 22% in the APR group. Patients treated with APR had a 25%, 5-year survival rate compared with 0% for those treated with LE, although one of the latter group died 55 months following LE due to unrelated causes without recurrence. The median survival of those with LE was 15.7 months and of those with APR 13.7 months.

CEA reactivity in amelanotic malignant melanoma of the anal canal

Amelanotic malignant melanoma can present a diagnostic problem in histopathology, especially when it presents in an extracutaneous location. In such cases electron microscopy and/or immunohistochemistry are invaluable for diagnosis. A 63-year-old women with rectal bleeding was found to have an amelanotic malignant melanoma of the anal canal, with compatible clinical and gross pathology and light and electron microscopic findings. Tumor cells showed positive staining with antibodies to vimentin, S 100 protein, and HMB-45 (melanoma-specific antibody), but also with polyclonal antibody to carcinoembryonic antigen (CEA). Tumor cells failed to stain with monoclonal antibody to CEA. The nature and significance of CEA reactivity in malignant melanoma are discussed.

Primary malignant melanoma of the rectum

The diagnosis of a primary rectal malignant melanoma has been the subject of considerable argument for many years, principally on the grounds that extension from a primary anal lesion was often impossible to exclude. This paper provides evidence that certain melanomas can be recognized as primary rectal tumours, not only from careful anatomical assessment of the site of the tumour, but also by showing that they arise on a background of benign melanocytic proliferation in the rectal mucosa. The clinical presentation of these lesions, their possible mechanism of origin and their treatment is discussed.