Unknown primary

Pelvic metastatic squamous cell carcinoma of unknown primary site: A case report and brief literature review

RATIONALE

Cancer with unknown primary site is a kind of disease that is difficult to deal with clinically, accounting for 2% to 9% of all newly diagnosed cancer cases. Here, we report such a case with pelvic metastatic squamous cell carcinoma of an unknown primary site and review the relevant literature.

PATIENT CONCERNS DIAGNOSES

A 43-year-old Chinese female patient was referred to our hospital and initially diagnosed as "malignant tumor of right adnexal area?, obstruction of right ureter, secondary hydronephrosis".

INTERVENTIONS

Thereafter cytoreductive surgery was performed which included a total hysterectomy, left adnexectomy, partial omentum resection, pelvic lymph node dissection, and para-aortic lymph node dissection. The primary lesion could not be identified by supplementary examination and postoperative pathology. The patient was diagnosed as pelvic metastatic squamous cell carcinoma whose primary site was unknown. To prevent a recurrence, we administered adjuvant chemotherapy for the patient.

OUTCOMES

The patient was followed up after treatment, complete remission has been maintained for 72 months, and no recurrence or metastasis has been found.

LESSONS

Our case demonstrates that surgery combined with chemotherapy could be helpful for pelvic metastatic squamous cell carcinoma of unknown primary site.

Colorectal Adenocarcinoma Metastasis to the Hard Palate: An Uncommon Site of Metastasis for a Common Malignancy

Colorectal adenocarcinoma (CRC) most commonly metastasizes to the peritoneum, liver, lung, and bone. Metastasis to the oral cavity is uncommon. Here, we report the case of a 74-year-old man who presented with a few months of chewing and swallowing difficulty, shoulder pain, and weight loss of 30 pounds. On oral exam, he was noted to have a 5 cm fixed hard palate mass. Primary hard palate malignancy was initially suspected. Biopsy of the mass confirmed adenocarcinoma with an immunohistochemical pattern suggestive of colorectal origin. He was later found to have extensive skeletal metastasis. Palliative radiotherapy to the hard palate region was initiated, followed by palliative systemic chemotherapy. We have found only three other published cases of rectal adenocarcinoma with hard palate metastasis.

Cancer of unknown primary inside the gastric wall identified by endoscopic submucosal dissection

We report the rare and interesting case of cancer of unknown primary (CUP) detected by endoscopic submucosal dissection (ESD). A 67-year-old man with a gastric adenoma was referred to our hospital for endoscopic treatment. Esophagogastroduodenoscopy revealed a 15-mm submucosal tumor (SMT) at the lesser curvature of the lower gastric body, near the gastric adenoma. Both lesions were resected by ESD. Pathological examination showed that the SMT was a poorly differentiated adenocarcinoma with lymphatic tissue. Additional surgical resection was performed, and the lymph nodes were found to have the same pathological findings as the SMT. These lesions were diagnosed as CUP because the obvious primary site was not detected with additional examination. The patient has been followed up for 24 months without recurrence.

Metastatic Tumour to the Mandible - A Diagnostic and Management Dilemma

Metastatic tumours of the jaw are overlooked due to their relatively rare incidence. However, they are often the first indicators of an unknown primary malignant lesion. In this case report, we present a 68-year-old male patient with a suspected intraosseous malignancy of the mandible who was treated by a right segmental mandibulectomy. The final histopathology report was indicative of a secondary metastatic tumour. Positron emission tomography scan revealed a suspicious lesion in the right lung, which was identified as the primary tumour by biopsy using the Tru-Cut® biopsy device (MeritMedical, Jordan UT). The metastatic lesion to the oral soft tissues was easily recognized, in contrast to the jawbone metastasis. Differentiating between primary intraosseous and metastatic mandibular tumours relies on the histopathologist and the surgeon working in tandem to arrive at an early conclusive diagnosis. Knowledge of metastatic tumours to the facial bones is indispensable to a surgeon as it can often be the first indication of an unknown primary malignancy. Identification of early signs, appropriate and timely investigative procedures, coordination between pathologist and surgeon, and choosing the correct treatment modality can help prolong and improve the quality of life of the patient.

Lobectomy for subsegmental lymph node metastasis of unknown origin

We report a very rare case of resected subsegmental lymph node metastasis of unknown origin. Hilar (N1) lymph node metastasis of unknown origin has previously been reported, but intrapulmonary lymph node metastasis has not been reported to date. At this patient's first visit to our hospital, an abnormal nodule was found on the upper lung lobe on a chest radiograph. After 4 years' follow-up, the nodule vanished, but a tiny nodule had emerged. 2-Fluoro-2-deoxy-D-glucose positron-emission tomography (FDG-PET) computed tomography was performed, and abnormal accumulation was observed only in the newly emerged intrapulmonary nodule. Right upper lobectomy was performed and a metastatic subsegmental lymph node, but no primary lesion, was found. Our observations suggest that evanescence of a suspicious primary lesion indicates the possibility of metastasis. FDG-PET was useful in this case for detecting lymph node metastases and demonstrating that the primary and further metastatic lesions were absent.

FDG PET/CT for metastatic squamous cell carcinoma of unknown primary of the head and neck

OBJECTIVE

The role of FDG PET/CT is uncertain in squamous cell carcinoma of unknown primary (SCCUP). Published data are limited by heterogeneity of pathology, varied diagnostic criteria, and small sample size.

MATERIALS/METHODS

This retrospective study was conducted in 40 patients who had FDG PET/CT for SCCUP. Prior to PET/CT, patients had underwent standard clinical evaluations including flexible rhinolaryngoscopy. The majority of the patients had anatomic imaging. All subjects had histopathological investigations, and follow-up data after PET/CT.

RESULTS

FDG PET/CT detected the primary in 16 of 40 patients (40%), and the most common locations of the primary were in the base of the tongue, palatine tonsil, and hypopharynx. There were 10 false positive and 6 false negative PET/CT scans. There was no difference in the mean SUVs of the suspected primary lesions between true and false positive groups. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy of FDG PET/CT for SCCUP in this patient cohort were 72.7% (16/22), 44.4% (8/18), 61.5% (16/26), 57.1% (8/14), and 60% (24/40), respectively. The tonsil was the site with the most false positive and false negative findings.

CONCLUSIONS

FDG PET/CT might be an effective single shot of whole-body imaging for detection of the primary in SCCUP. Low specificity remained the most notable weakness of FDG-PET in work-up for SCCUP. In addition to varied physiologic uptake or inflammatory related uptake in the common locations of the primary, the image indication bias might be another significant contributor of high false positive rate.

Diagnostic Value of 18F-FDG PET/CT in Patients with Carcinoma of Unknown Primary

Objective:

The aim of this study is to investigate the clinical role of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with carcinoma of unknown primary (CUP).

Methods:

One hundred twenty one patients with a diagnosis of CUP who underwent whole body ¹⁸F-FDG PET/CT imaging were included in this retrospective study. The final diagnoses were confirmed either histopathologically or by clinical follow-up.

Results:

The ¹⁸F-FDG-PET/CT successfully detected the primary tumor in 59 out of 121 (49%) patients. The most common primary tumor as detected by ¹⁸F-FDG PET/CT was lung cancer (n=31). In a patient, two primary tumors (colon and prostate) were detected on PET/CT imaging. Bone marrow biopsy revealed prostate cancer in this patient and the colon cancer was accepted as a synchronous second primary tumor. ¹⁸F-FDG PET/CT findings were false-positive in 11 patients. ¹⁸F-FDG PET/CT could not detect any primary lesion in 51 patients, whose conventional work-up detected a primary tumor in 11 and thus considered as false-negative. The sensitivity, specificity rate and accuracy of ¹⁸F-FDG PET/CT in detection of primary tumor were identified as 84%, 78% and 82%, respectively.

Conclusion:

Whole body ¹⁸F-FDG PET/CT is an effective method for detecting the primary tumor in patients with CUP. In addition to detecting the primary tumor, it can also help determine disease extent and contribute to patient management.

Advantages and disadvantages of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in carcinoma of unknown primary

Carcinoma of unknown primary is a type of malignant disease where the primary carcinoma cannot be identified by conventional examination, which presents challenges in diagnosis and therapy. This study aims to evaluate the detailed clinical value and indications of using fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F-18 FDG PET/CT) in a large sample. A total of 449 patients who were selected under strict standards were retrospectively included in this study. F-18 FDG PET/CT accurately detected the primary carcinoma in 115 of 449 patients whose primaries could not be detected by conventional examination (25.6%), with additional 27 false-positive patients. The most common primary site was the lung (34.8%). In addition, except for in metastatic melanoma (1/19, 5.3%) and axillary metastasis patients (2/49, 4.1%), F-18 FDG PET/CT had a comparative performance in detecting primary carcinoma in other pathological types and anatomical locations. The scan is able to guide treatment strategy modifications to some extent (130/449, 29.0%). We strongly recommend the use of F-18 FDG PET/CT in the early phase of examination. It is also recommended as a supplementary radiological method, and certain patients may benefit from its application in cases where regular examination is inconclusive. However, in metastatic melanoma or axillary metastasis patients where the primary site cannot be identified by routine examination, regular application of F-18 FDG PET/CT for the sole purpose of detecting the primary carcinoma should not be encouraged.

Hybrid imaging for detection of carcinoma of unknown primary: A preliminary comparison trial of whole-body PET/MRI versus PET/CT

PURPOSE

The aim of this study is to evaluate and compare the diagnostic potential of integrated whole-body [18F]FDG-PET/MRI to [18F]FDG-PET/CT for detection of a potential primary cancer and metastases in patients suspected for cancer of unknown primary (CUP).

METHODS

A total of 20 patients (15 male, 5 female, age 53±13 years) suspect for CUP underwent a dedicated head and neck & whole-body [18F]FDG-PET/CT (Biograph mCT 128, Siemens Healthcare) and a subsequent simultaneous [18F]FDG-PET/MRI examination (Biograph mMR, Siemens Healthcare). Two readers rated the datasets (PET/CT; PET/MRI) regarding the detection of the primary cancer and metastases, lesion conspicuity (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale). PET analysis comprised the assessment of maximum standardized uptake values (SUVmax) of all PET-positive lesions using volume of interest (VOI) analysis derived from the PET/CT and PET/MR datasets. All available data considering histology and imaging including prior and clinical follow-up examinations served as reference standard. Statistical analysis included comparison of mean values using Mann-Whitney U test and correlation of SUVmax using Pearson's correlation.

RESULTS

In 14 out of 20 patients 49 malignant lesions were present. The primary cancer could be correctly identified in 11/20 patients with both PET/CT and PET/MRI. PET/CT enabled the detection of a total 38 metastases, PET/MR respectively of 37 metastases (one lung metastasis <5mm was missed). PET/CT and PET/MRI showed comparably high lesion conspicuity (2.6±0.6 each), with superior assessment of cervical lesions in PET/MRI and an indicated superior assessment of pulmonary lesions in PET/CT. Diagnostic confidence was rated comparably high in PET/CT and PET/MRI (2.7±0.5 each). The mean values of SUVmax of all PET-positive lesions (PET/MRT 7.9±4.2 vs. PET/CT 7.2±3.5) showed a strong positive correlation between the SUVs derived from both hybrid imaging systems (Pearson's correlation r=0.927).

CONCLUSIONS

Both hybrid imaging techniques provide a comparable diagnostic ability for detection of primary cancer and metastases in patients with CUP, with comparably high lesion conspicuity and diagnostic confidence, offering superior assessment of cervical lesions in PET/MRI and potentially of pulmonary lesions in PET/CT. Furthermore, due to the significantly lower dose of ionizing radiation, PET/MRI may serve as a powerful alternative to PET/CT, particularly for therapy monitoring and/or surveillance considering the long-term cumulative dose.

Carcinoma of unknown primary in the head and neck: The evaluation of the effectiveness of (18)F-FDG-PET/CT, own experience

AIM

The aim of the present study was to estimate the clinical effectiveness of (18)F-FDG-PET/CT in the detection of the primary tumor in patients with histologically proven squamous cell carcinoma cervical lymph nodes metastasis from an unknown primary.

BACKGROUND

(18)F-fluorodeoxyglucose positron emission tomography combined with CT ((18)F-FDG-PET/CT) is believed to be very helpful in localization of primary tumor in CUP Syndrome patients.

MATERIAL AND METHOD

41 patients referred to Poznan Medical University Department of Head and Neck Surgery from January 2010 to December 2013 with CUP Syndrome were included in the study. All patients presented fine-needle biopsy proven squamous cell carcinoma metastasis of the upper-, or mid neck lymph nodes. The final results were obtained from the histopathologic reports of tissue samples from anatomical regions suspected for primary tumor, additional imaging exams as well as clinical follow-up data.

RESULTS

The (18)F-FDG-PET/CT successfully detected primary tumor in 7 out of 41 patients (17%). In two more cases the primary tumor was indicated in the lung. 24 of 41 patients (58.5%) analyzed in our study remained without evidence of a primary tumor. In 4 cases (9.75%) we did not reveal any pathology within the localizations indicated by PET/CT on panendoscopy. In 4 cases we obtained histological confirmation of neoplasm on panendoscopy despite the negative results of PET/CT examinations.

CONCLUSION

We may suppose a relatively high usefulness of (18)F-FDG-PET/CT in the diagnosis process of CUP Syndrome patients. High NPV may indicate patients with no symptoms of primary tumor, which allows to avoid extensive resection or extra imaging.

Osteosarcoma of the jaws: case report on synchronous multicentric osteosarcomas

Research has shown that osteosarcomas display high potential for metastasis to the lungs, pleurae and bones. Mandible, on the other hand, is an uncommon site for metastatic tumour cell colonization. Nevertheless, a metastatic tumour to mandible might be the first indication of an undiscovered malignancy at a distant site. This case report presents a case of a 61-year-old female patient. An osteosarcoma metastasized to her mandible shortly after the curettage of her jaw cyst. Both the metastatic osteosarcoma and the jaw cyst were confirmed by pathology. Initially, bilateral well-defined radiolucent lesions were shown in her panoramic X-ray image. Also, the diagnosis of a dentigerous cyst was made, based on histology. Two months later, a mixed radiolucent-radio opaque mass, which was confirmed as an osteosarcoma by pathology later, occupied the site of the previously enucleated dentigerous cyst, in her right mandible. Then, an identical osteosarcoma was found in the left pelvis on further doing overall radiological and pathological examinations. The pathologic hypotheses, treatment modality and follow-up of this case have also been presented.

The Role of 18 FDG PET-CT in Evaluation of Unknown Primary Tumours

An unknown primary tumor (UPT) is defined as a biopsy-proven malignancy whose anatomic origin remains unidentified after diagnostic evaluation. The estimated incidence of unknown primary tumors is 2 %-7 % of all malignancies. In 15-25 % of cases, the primary site cannot be identified even on postmortem examination. The management of these patients remains a clinical challenge. The aim of this study was to determine the role of 18FDG-PET CT in evaluation of primary tumor and its influence on therapeutic management. Fifty patients with histologically-proven metastases of UPT were included. For all patients, the conventional diagnostic work-up was unsuccessful in localizing the primary site. Whole-body PET/CT images were obtained approximately 60 min after intravenous injection of 350-425 MBq of (18) F-FDG. PET/(CT) depicted histologically verified primary tumors in 21of 46 patients (P > .05), achieving detection rates of approx. 61 % in patients presenting with cervical lymph node metastases from unknown primary tumors, and 40 % in those with extra cervical disease presentation. A positive predictive value of 72 % to 92 % was seen for all patients, depending on category of clinical presentation. In this study, PET/CT detection of additional metastases in 14.2 % (3 cases out of 21 true positives) influenced change in management plan. Considering recent studies and the results of this study, whole body FDG-PET/CT has to be considered a useful tool in evaluating metastases from an UPT, allowing an identification of primary tumors in 42 %, and modifying the stage of the disease and oncological treatment in about 50 % of cases. These results suggest the use of PET/CT with FDG in an early phase of the diagnostic evaluation to optimize the management of these patients.

Metastatic tumors to the gingiva and the presence of teeth as a contributing factor: a literature analysis

BACKGROUND

Gingiva that is prone to inflammation may serve as a pre-metastatic niche for the attraction of circulating malignant cells. The aim of this study is to analyze cases of metastatic lesions to the gingiva compared with cases metastasizing to other oral mucosal sites. The pathogenesis of gingival metastases is discussed, with emphasis on the role of inflammation.

METHODS

The English-language literature between 1916 and 2011 was searched for cases of metastatic lesions to the oral mucosa; only cases metastasizing in the oral mucosa, gingiva, and periodontium were included.

RESULTS

Two hundred seven cases were included. The gingiva was the most common site (60.4%), followed by tongue and tonsil. The most common primary sites were lung (24.2%), kidney (13.5%), skin (10.6%), and breast (8.7%). In 27%, the oral lesion was the first sign of a malignant disease. In most cases, the lesion appeared as an exophytic mass (96%) diagnosed clinically as a reactive gingival lesion. The presence of teeth was significantly associated with the development of gingival metastases: in 108 of 125 gingival metastases, the lesion was found adjacent to teeth (P <0.001; odds ratio = 8.2). The average life expectancy after diagnosis of the metastasis was 3.7 months.

CONCLUSIONS

The gingiva is the most common site for metastases to oral soft tissues, with strong association with the presence of teeth. This finding may be related to the role of inflammation in the attraction of metastatic cells to chronically inflamed gingiva.

Tumor margin identification and prediction of the primary tumor from brain metastases using FTIR imaging and support vector machines

Infrared spectroscopy enables the identification of tissue types based on their inherent vibrational fingerprint without staining in a nondestructive way. Here, Fourier transform infrared microscopic images were collected from 22 brain metastasis tissue sections of bladder carcinoma, lung carcinoma, mamma carcinoma, colon carcinoma, prostate carcinoma and renal cell carcinoma. The scope of this study was to distinguish the infrared spectra of carcinoma from normal tissue and necrosis and to use the infrared spectra of carcinoma to determine the primary tumor of brain metastasis. Data processing follows procedures that have previously been developed for the analysis of Raman images of these samples and includes the unmixing algorithm N-FINDR, segmentation by k-means clustering, and classification by support vector machines (SVMs). Upon comparison with the subsequent hematoxylin and eosin stained tissue sections of training specimens, correct classification rates of the first level SVM were 98.8% for brain tissue, 98.4% for necrosis and 94.4% for carcinoma. The primary tumors were correctly predicted with an overall rate of 98.7% for FTIR images of the training dataset by a second level SVM. Finally, the two level discrimination models were applied to four independent specimens for validation. Although the classification rates are slightly reduced compared to the training specimens, the majority of the infrared spectra of the independent specimens were assigned to the correct primary tumor. The results demonstrate the capability of FTIR imaging to complement histopathological tools for brain tissue diagnosis.

Clinical value of whole-body F-18 fluorodeoxyglucose positron emission tomography/computed tomography in patients with carcinoma of unknown primary

INTRODUCTION

The purpose of the study is to investigate the clinical value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in detecting the primary sites in patients with carcinoma of unknown primary (CUP).

METHODS

The reports of FDG PET/CT scans of 164 patients with CUP syndrome in consecutive 2589 patients referred to our department from January 2006 to June 2010 were retrospectively reviewed. The final results were obtained from the pathologic reports, other imaging modalities diagnoses and clinical follow-up data.

RESULTS

There were 142 cases in the results analysis, as 19 patients were lost to follow-up and three patients were excluded. FDG PET/CT successfully detected primary tumours in 67 (47.2%) out of 142 patients. Among this group, 53 were pathologically proved and 17 patients were confirmed by clinical follow-up. The primary sites of 38 (56.7%) were in lung, eight (11.9%) in nasopharynx and 13 (19.4%) in digestive system. Six patients were misdiagnosed by FDG PET/CT scan. FDG PET/CT could not detect the primary lesion in 66 patients, and three primary tumours were identified by conventional work-up after negative FDG PET/CT scan. The accuracy, sensitivity and specificity of FDG PET/CT scan in detecting the primary site in this study were 93.7%, 95.7% and 91.7%, respectively. FDG PET/CT scan changed the medical management of about 33.8% of 142 CUP patients.

CONCLUSION

FDG PET/CT whole-body imaging is a valuable tool in detecting the primary tumour of patients with CUP site.

Metastatic carcinomas to the oral cavity and oropharynx

Background

Metastases to the oral/oropharynx are very rare and their diagnosis is challenging.

Methods

We reviewed pathologic data for malignant tumors of the oral/oropharynx that were diagnosed at the Asan Medical Center, Seoul, Korea from 1995 until 2010.

Results

Twenty-nine cases of oral/oropharyngeal metastases were retrieved, comprising 2.0% of 1,445 malignancies. The most common primary sites were the liver and lung, followed by the stomach, colon, breast, prostate, and kidney. The gingiva was the most common metastatic site, followed by the tonsil/pillar, mandible, tongue, tongue base, palate mucosa, mouth floor, and buccal mucosa. Intervals between detection of primary tumors and metastases were variable, from -1 month to 104 months. Ten patients with lung (7 cases), liver, stomach, and kidney carcinomas manifested with oral/oropharyngeal metastases as the first sign of systemic metastases. The majority of patients had died within one year of the onset of an oral/oropharyngeal metastasis, but exceptionally long-lived cases were also present. The survival periods of patients with lung cancers were longer than those of patients with non-pulmonary tumors.

Conclusions

An awareness of the incidence, common primary sites, metastatic subsites, and metastatic courses or patterns of oral/oropharyngeal metastases is helpful in the diagnosis of metastatic carcinomas.

[Pathohistology and molecular genetic diagnostics in CUP syndrome]

Patients with cancers of unknown primary (CUP syndrome) represent a relatively large group of cancer patients (5-10%) in whom the histomorphological diagnosis is made from tissue from the metastasis, and the site of the primary tumour remains unclear. The incidence is variable, depending on the definition used and the intensity of the search for a primary tumour. From a biological and prognostic point of view, it is helpful to distinguish eight clinical entities of the CUP syndrome; four of these entities can be subdivided histologically. Histopathologic diagnosis should be performed using a diagnostic algorithm based on the HE morphology and supplemented by immunohistochemistry. With the use of a broad spectrum of immunohistochemical markers, many tumour entities can be diagnosed, so in most cases molecular genetic investigations are not necessary.

Head and neck manifestations of distant carcinomas

Metastatic tumors to the head and neck from distant carcinomas are rare lesions that epitomize the "zebras." They represent a diagnostic and therapeutic challenge for clinicians and health providers. These lesions usually rank low in the differential diagnosis list, but a history of cancer should prompt clinicians about the possibility of a metastatic lesion from a distant carcinoma. The presence of these lesions usually represents a poor prognosis. The surgeon's role in treating these lesions is to improve or maintain the patient's quality of life, taking into consideration the overall prognosis.

Metastatic tumours to the oral cavity - pathogenesis and analysis of 673 cases

The oral region is an uncommon site for metastatic tumour cell colonization and is usually evidence of a wide spread disease. In 25% of cases, oral metastases were found to be the first sign of the metastatic spread and in 23% it was the first indication of an undiscovered malignancy at a distant site. The jawbones, particularly the mandible, were more frequently affected than the oral soft tissues (2:1). In the oral soft tissues, the attached gingiva was the most commonly affected site (54%). The major primary sites presenting oral metastases were the lung, kidney, liver, and prostate for men, breast, female genital organs (FGO), kidney, and colo-rectum for women. The primary site differs according to oral site colonization, in men the lung was the most common primary site affecting both the jawbones and oral mucosa (22% and 31.3%, respectively) followed by the prostate gland in the jawbones (11%) and kidney in the oral soft tissues (14%). In women, the breast was the most common primary tumour affecting the jawbones and soft tissues (41% and 24.3%, respectively), followed by the adrenal and female genital organs (FGO) in the jawbones (7.7%) and FGO in the soft tissues (14.8%). The clinical presentation of the metastatic lesions differ between the various sites in the oral region. In the jawbones most patients complain of swelling, pain and paresthesia which developed in a relative short period. Early manifestation of the gingival metastases resembled a hyperplastic or reactive lesion, such as pyogenic granuloma, peripheral giant cell granuloma, or fibrous epulis. Because of its rarity, the diagnosis of a metastatic lesion in the oral region is challenging, both to the clinician and to the pathologist, in recognizing that a lesion is metastatic and in determining the site of origin. The clinical presentation of a metastatic lesion in the oral cavity can be deceiving leading to a misdiagnosis of a benign process, therefore, in any case where the clinical presentation is unusual especially in patients with a known malignant disease a biopsy is mandatory.

Metastatic melanoma to lymph nodes in patients with unknown primary sites

BACKGROUND

The natural history of metastatic melanoma in lymph nodes in the absence of a known primary site (MUP) has been defined poorly; thus, treatment guidelines for patients with MUP are not clear-cut.

METHODS

The authors conducted a retrospective analysis of consecutive patients with melanoma (from 1990 to 2001) who underwent surgical resection for melanoma metastatic to regional lymph nodes. Among those patients, 71 patients with MUP and 466 control patients who had regional lymph node metastases of similar stage with a known primary site were identified. Associations between clinicopathologic factors and survival were estimated by using the Cox proportional hazards model.

RESULTS

After they underwent lymph node dissection, patients with MUP were classified with N1b disease (47%), N2b disease (14%), or N3 disease (39%). With a median follow-up of 7.7 years, the 5-year and 10-year overall survival rates were 55% and 44%, respectively, for patients with MUP, compared with 42% and 32%, respectively, for the control group (P = .04). In multivariate analyses, age 50 years or older, male gender, and N2b or N3 disease status were identified as adverse prognostic factors, and MUP was identified as a favorable prognostic factor (hazard ratio, 0.61; 95% confidence interval, 0.42-0.86; P = .006) for overall survival.

CONCLUSIONS

The relatively favorable long-term survival of patients with MUP in the current study suggested that patients with MUP have a natural history that is similar to (if not better than) the survival of many patients with Stage III disease. Therefore, patients with MUP should be treated with an aggressive surgical approach with curative intent and should be considered for Stage III adjuvant therapy protocols. Cancer 2006. (c) 2006 American Cancer Society.