Amelanotic malignant melanoma of the esophagus: Report of two cases with immunohistochemical and molecular genetic study of KIT and PDGFRA

Metanephric stromal tumor in an adult with PDGFRA mutation: a case report

BACKGROUND

Metanephric stromal tumors (MST) are rare benign renal tumors that mainly occur in infants and children. Approximately 72% of MST in children have the B-Raf proto-oncogene serine/threonine kinase (BRAF) V600E mutation. To date, only five cases of adult MSTs have been reported and no clear genetic alterations have been found.

CASE PRESENTATION

We report a case of MST in a 45-year-old woman who complained of left lower back pain for a week, accompanied by hypertension (150/79 mmHg). Magnetic resonance imaging (MRI) showed an abnormally enhanced nodule (1.1 cm in the middle of the left kidney), which was histopathologically consistent with an MST. The BRAF V600E mutation was not detected in tumor cells using PCR and next-generation sequencing (NGS). However, a platelet-derived growth factor receptor alpha (PDGFRA) mutation was detected in this case using NGS. The patient showed no recurrence or metastasis nine months after partial nephrectomy, and her blood pressure was consistently normal.

CONCLUSION

This is the first report of alterations in PDGFRA in MSTs. This result advances our knowledge of genetic variations in adult MSTs, which may have different gene alterations from MSTs in children.

Comprehensive clinicopathological and molecular analysis of primary malignant melanoma of the oesophagus

AIMS

This study was performed to elucidate the clinicopathological characteristics, genetic alterations and therapeutic targets of primary malignant melanoma of the oesophagus (PMME).

METHODS AND RESULTS

The clinicopathology and molecular pathology of 13 PMME cases and 10 skin malignant melanoma (SKMM) cases were analysed with next-generation sequencing (NGS) and immunohistochemistry. The 3-year overall survival rate and the median survival time for PMME patients were 23.1% and 11.9 months, respectively. Three (23.1%) and eight (61.5%) PMME cases showed a papillary structure and lymph node metastasis, respectively. DNA and RNA hybridization capture-based NGS analysis revealed that NF1 was the most frequently mutated gene (30%) in 10 of the PMME cases. Other mutations detected in PMME included SF3B1 (20%), KRAS (10%), BRCA2 (10%), KIT (10%) and TP53 (10%) mutations. Commonly detected BRAF mutations in SKMM were not detected in PMME. Immunohistochemistry and mutation status were concordant between p53/c-Kit and TP53/KIT, respectively. Focal expression of programmed death-ligand 1 was observed in one PMME sample. The tumour mutation burden in PMME was significantly lower than that in SKMM (P = 0.030). No PMME case showed high microsatellite instability. RNA sequencing revealed a distinctive pattern with respect to RNA expression. T-cell co-stimulation differed between PMME and SKMM.

CONCLUSIONS

The RAS-mitogen-activated protein kinase pathway is one of the main pathways involved in PMME. The genetic profile of PMME was similar to that of mucosal/acral melanoma, but differed from the SKMM profile. A subset of PMMEs may contain actionable mutations. Immunotherapy seemed to be less effective for most PMMEs in this series.

Genetic mutations in primary malignant melanoma of the esophagus: case report and literature review

The most frequent genetic aberrations in mucosal melanoma are activating mutations of c-KIT. Primary malignant melanomas of esophagus (PMME) are uncommon entities, with aggressive biological behavior and poor prognosis. The better definition of their genotype could improve therapeutic options. We report a case of a 66 years old man with a PMME in the lower third of the esophagus. Analysis of c-kit, KRAS, NRAS and BRAF genes resulted negative for mutations. On the basis of a computerized (PuMed/Medline) bibliography search we retrieved a total of other 35 cases of PMME analyzed for genetic alterations in RAS, BRAF, and KIT. When we compared mutations frequency of PMME with those of other mucosal melanomas, it appeared that PMME are characterized by a relative higher percentage of NRAS mutations. PMME seem to show a specific pattern of genetic alterations suggesting that they could represent a distinct entity among mucosal melanomas.

Primary malignant melanoma of esophagus: clinicopathologic characterization of 20 cases including molecular genetic profiling of 15 tumors

Primary malignant melanoma of esophagus is very rare, and its clinicopathologic and genetic features have not been extensively investigated. In this study, 20 tumors from 14 male and 6 female patients (40-79 years old) were evaluated. Dysphagia, chest pain, and weight loss were frequent symptoms. Thirteen melanomas, including two with multiple lesions, involved the distal third of esophagus. The median tumor diameter was 6 cm. Epithelioid morphology, moderate atypia, and pigmentation were typical findings. None of the patients had melanoma elsewhere, and all tumors exhibited a junctional peri-epithelial component consistent with a primary lesion. The median mitotic activity was 11 per 10 high-power fields (range, 0-31). Nine patients died of tumor within 4-22 months, however, two showed long-term (96 and 104 months) survival. In 15 cases, tissue for further immunohistochemical and molecular studies were available. BRAF, KIT, and NRAS mutation status was assessed by Sanger sequencing in all 15 tumors. The next-generation sequencing of 50 or 409 genes was performed in five and three cases, respectively. IGF1R expression indicating activation of the IGF axis was seen in 82% (9/11) of tumors. However, no BRAF mutations were identified. In 33% (5/15) of tumors, NRAS mutations were detected. KIT expression was seen in 50% (7/14) of melanomas including single KIT mutant. Two of three tumors evaluated with 409 genes panel revealed multiple driver mutations indicating sub-clonal expansion, whereas a single mutation (TSC1 p.H371Q) was the sole change in the third case. SF3B1 p.K666T and p.R625C mutations were detected in two cases. However, no co-occurrence of SF3B1 and GNAQ or GNA11 mutations, seen in uveal melanoma, was detected. FBXW7 p.R465C and p.R479G mutations, linked to cancer progression, were found in two of eight tumors. In summary, esophageal melanoma mutation profile indicates complexity of molecular mechanisms underlying its pathogenesis.

Primary amelanotic malignant melanoma of the esophagus: a case report

Background

Primary amelanotic malignant melanoma of esophagus, which is a subtype of primary malignant melanoma of the esophagus (PMME), is a very rare disease with a poor prognosis. We herein report a case of the amelanotic type of PMME.

Case presentation

An 86-year-old woman was admitted to our hospital with symptoms of dysphagia. An endoscopic examination and constructed radiography revealed an elevated and semipedunculated lesion with an ulcer in the lower thoracic esophagus accompanied by another submucosal lesion of the esophagus. She was diagnosed with esophageal squamous cell carcinoma by a preoperative endoscopic biopsy. We performed thoracoscopy- and laparoscopy-assisted subtotal esophagectomy with lymphadenectomy. Based on the surgical specimens, although there were no melanocytes, we made a diagnosis of a malignant melanoma immunohistochemically; the tumor cells were positive for S-100 protein and HMB45 focally and partially for Melan-A.

Conclusion

We experienced a case of primary amelanotic malignant melanoma, and the patient has remained disease-free for 1 year since the surgery. Since the diagnosis of amelanotic type of PMME is difficult, it should be made by the combination of a morphological examination, pathological examination, and immunohistochemistry.

A report of amelanotic malignant melanoma of the esophagus diagnosed appropriately with novel markers: A case report

The present case study reported of amelanotic malignant melanoma of the esophagus. A 68-year-old man underwent laparoscopic distal gastrectomy for early gastric cancer diagnosis. After gastrectomy, endoscopic examination revealed a protruded lesion lying adjacent to the melanosis area of the esophagus. Histology of the biopsy specimen suggested malignancy, but the diagnosis could not be made. The patient underwent trans-thoraco-abdominal curative subtotal esophagectomy. Immunohistochemical examination of the resected specimen was negative for HBM-45 and Melan-A. However, immunohistochemical examinations of SOX10 (Sry-related HMg-Box gene 10) and KBA.62, which are not associated with melanosome, were strongly positive, and tyrosinase was notably positive. A diagnosis primary of amelanotic malignant melanoma of the esophagus that consisted of only premelanosomes was made. The present findings suggest that, in the diagnosis of malignant melanoma, SOX10 and KBA.62 may be useful, particularly in diagnosing amelanotic malignant melanoma.

A tenebrous tale: malignant melanoma of the oesophagus

A 57-year-old man presented with a 4-month history of worsening symptoms of oesophageal obstruction. The physical examination was unremarkable. An oesophagogastroduodenoscopy revealed an exophytic tumour in the distal oesophagus. A biopsy demonstrated malignant melanoma. Staging of the melanoma showed disseminated lymph node and bony-spine metastases. He had no prior history of cutaneous or ocular melanoma. Following full multidisciplinary team input, he was palliated with a metal mesh stent and immunotherapy. He died 3 months later following community management.

Decidualization of uterine adenomyoma in a pregnant woman: a case report with immunohistochemical study

BACKGROUND

Decidualization of uterine adenomyoma has not been reported, to the best of the author's knowledge.

AIM

To report a case of uterine adenomyoma with decidualization.

CASE REPORT

A 43-year-old pregnant woman with "myoma" underwent cesarean operation and "myomectomy" at 37 gestation weeks. The operation was successful, and the baby and mother were healthy. Grossly, the "myoma" measured 12 × 10 × 10 cm, and the consistency was firm. Microscopically, the tumor was adenomyoma consisting of smooth muscle bundles and endometrial islands. Characteristically, the endometrial stroma showed marked decidualization. An immunohistochemical study showed that the decidual cells were positive for pancytokeratin AE1/3, pancytokeratin CAM5.2, cytokeratin (CK)7, CK18, vimentin, CA125, CD10, estrogen receptor (ER), progesterone receptor (PgR), and Ki-67 (labeling 1 %). They were negative for CK34βE12, CK5/6, CK8, CK14, CK19, CK20, EMA, p63, desmin, α-smooth muscle actin, S100 protein, CK34, CD68, and p53. These results show that marked decidualization occurs in adenomyoma during pregnancy, and that the decidual cells are positive for pancytokeratin AE1/3, pancytokeratin CAM5.2, CK7, CK18, vimentin, CA125, CD10, ER, and PgR.

CONCLUSION

A rare case of uterine adenomyoma with decidualization is reported.

Amelanotic malignant melanoma of the cervical oesophagus

We report the case of a young woman who presented with progressive dysphagia and swelling in the anterior aspect of the neck of short duration. On evaluation, she was diagnosed with amelanotic malignant melanoma of the cervical oesophagus. She underwent total laryngopharyngo-oesophagectomy with gastric transposition with bilateral modified radical neck dissection with feeding jejunostomy and a permanent tracheostomy with postoperative combined chemoradiation therapy. However, in spite of aggressive treatment, the patient expired 8 months after initial presentation with distant metastasis.

Pseudomyxoma cutis; a new entity

Pseudomyxoma (PM) implies an accumulation of a large amount of mucins which show myxomatous appearances. PM Peritonei (PMP) is famous and the only example of PM. PMP means excessive accumulation of mucins and mucin-secreting cells in the peritoneal cavity. The causes of PMP are mostly mucinous tumors, both benign and malignant, of ovaries and vermiform appendix. The author experienced excessive accumulation of mucins and mucin-producing cells in the subcutis and deep soft tissue. This situation very resembled PMP. Thus, the author termed the lesion as PM cutis (PMC). A 57-year-old man admitted to our hospital because of multiple subcutaneous large tumors in the perianal skin. The tumors were deeply seated and soft. No biopsy was performed. Very large skin and subcutis resection of the perianal region was done. Grossly, the material was skin and sot tissue flap measuring 25x25x5cm. The subcutis and deep soft tissue were resected. On cut surface, the tumor was slimy liquid. Microscopical examination revealed a large amount of mucins pools and mucin-producing intestinal epithelium with mild atypia. The author diagnosed it metastatic extremely well differentiated adenocarcinoma producing mucins, and pointed out anorectal primary. Thus, Miles operation was performed, which showed tumor formation in the anus. The tumor was located from the submucosa to adventitia, and composed of mucin pools and mucins producing intestinal-type epithelium with atypia. Mucins histochemistry showed that the mucin pools and epithelial cytoplasm contained neutral, carboxylated, and sulfated mucins. Immunohistochemically, the tumor cells were positive for CKAE1/3, CKCAM5.2, CK7, CK8, CK19, CK20, CEA, CA19-9,CD68, MET, p53, MUC2, MUC5AC, KIT, PDGFRA, chromogranin, and Ki-67 (76%). They were negative for CK34BE12, CK5/6, CK14, CK18, EMA, vimentin, desmin, smooth muscle actin, p63, CD34, ER, PgR, CA125, MUC1, MUC6, CD45, CD10, synaptophysin, surfactant Apo-A, TTF-1, NCAM, bcl-2, CDX-2. Although the atypia is mild, the author diagnosed primary anorectal extremely well differentiated adenocarcinoma with excessive production of mucins. The author considers the cutaneous mucins and tumor cells are metastatic or directly invading lesions of the anal tumor. Thus, the author termed pseudomyxoma cutis (PMC) for the cutaneous lesion.

Urinary bladder urothelial carcinoma with expression of KIT and PDGFRA and showing diverse differentiations into plasmacytoid, clear cell, acantholytic, nested, and spindle variants, and into adenocarcinoma, signet-ring cell carcinoma, small cell carcinoma, large cell carcinoma, and pleomorphic carcinoma

Various tumors can arise in the urinary bladder (UB); most common is urothelial carcinoma (UC). UC of the UB have many variants. Other types of carcinomas such as adenocarcinoma (AC) and small cell carcinoma (SmCC) can occur in UB carcinomas. Expression of KIT and PDGFRA has not been reported. A 66-year-old man admitted to our hospital because of hematuria. Cystoscopy revealed papillary invasive tumor and a transurethral bladder tumorectomy (TUR-BT) was performed. The TUR-BT showed UC, AC, SmCC, large cell carcinoma (LCC), and pleomorphic carcinoma (PC). The UC component showed plasmacytoid, spindle, nested, clear cell, acantholytic variants. The AC element showed tubular adenocarcinoma and signet-ring cell carcinoma (Sig). Immunohistochemically, all of these subtypes were positive for cytokeratin (CK) AE1/3, CK CAM5.2, CK34BE12, CK5, CK6, CK7, CK8, CK18, CK19, CK20, EMA, CEA, p63, CA19-9, p53 (positive 45%), MUC1, NSE, NCAM, KIT, PDGFRA, and Ki-67 (87%). They were negative for vimentin, chromogranin, synaptophysin, S100 protein, CD34, CD14, α-smooth muscle actin, CD31, caldesmon, CD138, CD45, κ-chain, λ-chain, MUC2, MUC5AC and MUC6. Mucin histochemistry revealed mucins in AC element including Sig. A molecular genetic analysis using PCR-direct sequencing method identified no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The carcinoma was highly aggressive and invaded into muscular layer. The nuclear grade was very high, and there were numerous lymphovascular permeations were seen. The surface showed carcinoma in situ involving von-Brunn's nests. This case shows that carcinoma of UB can show diverse differentiations into numerous histological types and variants, and can express KIT and PDGFRA. The both genes showed no mutations in the present case.

Adenoid cystic carcinoma of the oral cavity: immunohistochemical study of four cases

Adenoid cystic carcinoma (ACC) in the oral cavity is rare, and no immunohistochemical studies of ACC in the oral cavity have been performed. This report describes the immunohistochemical study of four ACCs of the oral cavity. The male to female ratio was 1:3. The age was 43, 51, 59 and 64 years. The location was tongue (n=2), buccal mucosa (n=1), and gingiva (n=1). Histochemically, all ACCs were positive for neutral, carboxylated and sulfated mucins. Immunohistochemically, ACC was consistently positive for cytokeratin (CK) AE1/3, CK 34βE12, CK5/6, CK7, CK14, CK18, p63, CA19-9, c-KIT (CD117), PDGFRA, MUC1, and Ki-67 (labeling index: 5%, 15%, 20% and 40%). ACC was consistently negative for CK8, CK20, desmin, S100 protein, CD34, chromogranin, MUC2, MUC5AC and MUC6. Some ACCs were positive for CK CAM5.2 (3/4), CK19 (1/4), EMA (2/4), CEA (2/4), vimentin (3/4), α-smooth muscle actin (2/4), p53 (2/4), CD10 (2/4), and synaptophysin (1/4). These results may provide basic knowledge of ACC of the oral cavity.

Primary cutaneous neuroendocrine tumor (atypical carcinoid) expressing KIT and PDGFRA with myoepithelial differentiation: a case report with immunohistochemical and molecular genetic studies

Primary cutaneous neuroendocrine tumors (NET) except for Merkel cell carcinoma have rarely been reported. Herein reported is a very unique case of primary cutaneous NET with immunohistochemical markers of myoepitheliomas. A 47-year-old woman presented a tumor measuring 0.8x0.9x0.6 cm of the face. The tumor was excised completely with wide margins. Morphologically, the tumor was located in the dermis, and the tumor was composed of epithelioid cells arranged in trabecular, sinusoidal, rosette, ribbon-like, and cord-like patterns. Focal areas show tubular formations. The tumor cells were homogenous, and their nuclei showed hyperchromasia but no apparent histological features of malignancy were seen. The stroma was very scant. No invasive features were seen. Immunohistochemically, the tumor cells were strongly positive for cytokeratin (CK) 34BE12, CD5/6, CK14, NCAM (CD56), p63, and KIT (CD117), and moderately positive for CK AE1/3, p53, chromogranin, synaptophysin, neuron-specific enolase (NSE), PDGFRA, CA19-9, and Ki-67 antigen (labeling index=23%). The tumor cells were negative for CK CAM5.2, CK7, CK8, CK18,CK19,CK20, EMA, vimentin, CEA, HMB45, S100 protein, α-smooth muscle antigen, desmin, CD34, GFAP, neurofilaments, CD99 (MIC2), CD45, CD57, ErbB2, TTF-1, MUC1, MUC2, MUC5AC, and MUC6. Mucins examined by d-PAS and Alcian blue techniques were negative. A genetic analysis using PCR-direct sequencing method in paraffin sections identified no mutations of KIT (exons 9, 11, 13 and 17) and PDGFRA (exons 12 and 18) genes. Imaging modalities including CT and MRI identified no tumor in the body. The clinicians thought that the tumor was cured. She was a sailor and immediately visited other countries; therefore the follow-up could not be done.

A clinicopathologic study of esophageal 860 benign and malignant lesions in 910 cases of consecutive esophageal biopsies

The author reviewed 910 cases of consecutive esophageal biopsies in the last 15 year in the pathology laboratory of our hospital. There were 693 normal mucosa and benign lesions (76.2%) and 217 malignant lesions (23.8%). No significant changes were recognized in the esophagus in 50 biopsies (5.5%). In benign lesions, the number and frequency (percentages) were as follows: 263 chronic esophagitis (28.9%), 98 heterotopic gastric mucosa (10.8%), 3 heterotopic colonic mucosa (0.3%), 71 glycogenic acanthosis (7.8%), 68 candidiasis (7.5%), 35 benign ulcer (3.8%), 41 squamous papilloma (4.5%), 4 granular cell tumor (0.4%), 1 tubular adenoma (0.1%), 2 cytomegalovirus esophagitis (0.2%), 3 leiomyoma (0.3%), 17 basal cell hyperplasia (1.9%), and 37 Barrett's epithelium (4%). In malignant lesions, the number and frequency (percentages) were as follows: 53 mild dysplasia (5.8%), 29 moderate dysplasia (3.2%), 31 severe dysplasia (3.4%), 13 carcinoma in situ (1.4%), 68 squamous cell carcinoma (7.5%), 7 primary adenocarcinoma (0.8%), 1 primary signet ring cell carcinoma (0.1%), 4 primary small cell carcinoma (0.4%), 2 primary amelanotic malignant melanoma (0.2%), 1 primary undifferentiated sarcoma (0.1%), 7 gastric cancer invasion (0.8%), and 1 primary adenoid cystic carcinoma (0.1%). In this article, the clinicopathologic features of these esophageal lesions were described.

Projected focal nodular hyperplasia of the liver with pronounced atypical ductular reaction resembling ductal plate and expressing KIT

A 26-year-old woman was found to have a left abdominal tumor in the space among the hepatic left lobe, stomach and spleen. A laparoscopic examination revealed that the tumor was a projected liver tumor, and resection of the tumor was performed. Grossly, the tumor was not encapsulated and measured 4 cm × 4 cm × 5 cm. Microscopically, the tumor was composed of mature hepatocytes, fibrous septae, abnormal vessels and ductular reaction (DR). A pathological diagnosis of projected focal nodular hyperplasia (FNH) was made. Characteristically, the cells of the DR showed atypical features such as small cells and hyperchromatic nuclei. The DR assumed the features of ductal plate-like structures and immunohistochemically expressed KIT, suggesting that the cells of DR are stem cells and that when the stem cells proliferate they take a form of ductal plate-like structures, similar to fetal bile duct development. Immunohistochemically, the cells of DR were positive for cytokeratin (CK) AE1/3, CK CAM5.2, CK7, CK8, CK18, CK19, carcinoembryonic antigen (CEA), CA19-9, Ki-67 (labeling = 3%) and KIT, but negative for CK20, p53, TTF-1, CDX2, MUC1, MUC2, MUC5AC and MUC6. The hepatocytes were positive for CK CAM5.2, CK8, CK18 and Ki-67 (labeling = 4%), but negative for CK AE1/3, CK7, CK19, CK20, CEA, CA19-9, p53, KIT, TTF-1, CDX2, MUC1, MUC2, MUC5AC and MUC6. In conclusion, the author reported a projected FNH. The DR of the FNH showed atypical features such as small cells and hyperchromatic nuclei. The DR assumed features of ductal plate-like structures. KIT was positive in the DR in the FNH, suggesting that the cells of DR are liver stem cells, and proliferation of these cells take features of ductal plate-like structures, similar to embryonic biliary development. MUC apomucins are negative in the DR.

An immunohistochemical and molecular genetic analysis of KIT and PDGFRA in small cell lung carcinoma in Japanese

KIT and PDGFRA in small cell lung carcinoma (SCLC) have been rarely examined in Japanese. The author investigated protein expression of KIT and PDGFRA in 54 Japanese cases of small cell lung carcinoma by immunohistochemistry, and gene mutations of KIT and PDGFRA in 20 Japanese cases of small cell lung carcinoma by the PCR-direct sequencing method. The molecular genetic analysis showed no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes in all 20 cases. KIT protein expression was recognized in all cases (100%). Membranous KIT expression was strong in 35 cases, moderate in 7 cases and weak in 12 cases. PDGFRA protein expression was noted in 35 cases (65%); the membranous expression was strong in 2 cases, moderate in 16 cases, and weak in 17 cases. The overall median survival was 13 months. There was no significant difference in the survival between KIT strongly positive cases (median, 12 months) and KIT moderately or weakly positive cases (median, 11 months). Likewise, there was no significant difference in the survival between PDGFRA-positive cases (median, 11 months) and PDGFRA-negative cases (median, 12 months). The protein expressions of KIT and PDGFRA did not correlate with gender, smoking, and disease stage. These findings suggest, in Japanese population, that mutations of KIT and PDGFRA were absent in small cell lung carcinoma of Japan, that KIT protein expression is present in 100%, that PDGFRA expression is present in 65%, and that KIT and PDGFRA protein expressions do not correlate with survival, gender, smoking, and disease stage.

Malignant melanoma of the conjunctiva: a case report with examination of KIT and PDGFRA

Although many clinicopathological studies of malignant melanoma of the conjunctiva have been reported, there have been no studies of the expression and gene mutations of KIT and PDGFRA in melanoma of the conjunctiva. A 69-year-old Japanese woman consulted our hospital because of black mass (0.7 × 0.7 × 0.6 cm) in the conjunctiva. A biopsy was taken. The biopsy showed malignant epithelioid cells with melanin deposition. Immunohistochemically, the tumor was positive for S100 protein, HMB45, p53, Ki-67 (labeling=30%), KIT and PDGFRA. The tumor was negative for pancytokeratins (AE1/3 and CAM5.2). A genetic analysis using PCR-direct sequencing revealed no mutations of KIT gene (exons 9, 11, 13, and 17) and PDGFRA gene (exons 12 and 18). The pathological diagnosis was conjunctival melanoma. Despite chemotherapy, the patient developed multiple metastases of melanoma, and died of melanoma 7 years after the biopsy. In conclusion, the author reported a case of melanoma of conjunctive expressing KIT and PDGFRA proteins without gene mutations of KIT and PDGFRA.

Malignant melanoma of the nasal cavity: a case report with examination of KIT and platelet derived growth factor receptor-α(PDGFRA)

Although several clinicopathological studies of malignant melanoma of the nasal cavity have been reported, there are no studies of the expression and gene mutation of KIT and platelet derived growth factor receptor-α (PDGFRA) in melanoma of the nasal cavity. A 92-year-old Japanese woman consulted to our hospital because of right nasal obstruction and epistaxis. Physical examination and imaging modalities showed a tumor of the right nasal cavity. A biopsy was taken, and it showed malignant epithelioid cells with melanin deposition. Immunohistochemically, the tumor was positive for S100 protein, HMB45, p53, Ki-67 (labeling=20%), KIT and PDGFRA. The tumor was negative for cytokeratins (AE1/3 and CAM5.2). A genetic analysis using PCR-direct sequencing revealed no mutation of KIT gene (exons 9, 11, 13, and 17) or the PDGFRA gene (exons 12 and 18). The pathological diagnosis was primary malignant melanoma of the nasal cavity. The tumor was reduced in size by local resection and chemotherapy (Darthmose regimen: dacarbazine, carmustine, cisplatine, and tamoxifen), and the patient is now alive and free from metastasis 9 months after the first manifestation. In conclusion, the author reported a case of melanoma of the nasal cavity expressing KIT and PDGFRA without gene mutations of KIT and PDGFRA.

Genetic aberrations in primary esophageal melanomas: molecular analysis of c-KIT, PDGFR, KRAS, NRAS and BRAF in a series of 10 cases

We present a series of 10 primary esophageal melanomas of Caucasian patients characterized clinicopathologically and on the molecular level. Mutation analysis for c-Kit (exons 9, 11, 13 and 17), PDGFR (exons 12, 14 and 18), NRAS and KRAS were determined using PCR and direct sequencing. Analysis of the V600E mutation of BRAF was performed using mutation-specific PCR. Expression of c-Kit and PDGFR-A was additionally determined using immunohistochemistry. One tumor harbored a missense mutation in the c-Kit (p.F504L) and in the KRAS gene (p.G12S). A different c-Kit mutation (c.1507_1508 ins TTGCCT) was detected in another case. A third case had a V600E BRAF mutation. Using immunohistochemistry, c-Kit expression could be detected in all cases. The two cases with c-Kit mutations showed high c-Kit expression. None of the tumors showed a PDGFR mutation or expression or a NRAS mutation. We conclude that molecular analysis can identify targets for a specific therapy such as tyrosin kinase inhibitors as additional treatment option in these highly malignant tumors.