Sentinel lymph node biopsy for evaluation and treatment of patients with Merkel cell carcinoma: The Dana-Farber experience and meta-analysis of the literature

OBJECTIVE

To determine the diagnostic accuracy and usefulness of sentinel lymph node biopsy (SLNB) and computed tomographic scans in the initial evaluation and treatment of patients with Merkel cell carcinoma (MCC).

DESIGN

Single-institution case series and literature-based case-level meta-analysis.

SETTING

Academic cutaneous oncology clinic.Patients Sixty-one adults with biopsy-proven MCC (30 who had undergone SLNB) plus 92 cases from the literature of patients who had undergone SLNB.

MAIN OUTCOME MEASURES

Relapse-free survival.

RESULTS

In 122 patients with no nodal disease found by physical examination, SLNB findings revealed nodal involvement in 39 cases (32%). At 3 years, the recurrence rate for those with a positive SLNB was 3 times (60%) higher than for those with a negative SLNB (20%; P = .03). Patients with a positive SLNB who received adjuvant nodal therapy had a relapse-free survival rate of 51% at 3 years (n = 26) compared with 0% for patients who did not receive nodal therapy (n = 3; P < .01). In contrast, among patients with a negative SLNB there was no significant difference in 3-year relapse-free survival rates for those who did (90%; n = 24) or did not (70%; n = 19; P = .26) receive adjuvant nodal therapy. Using SLNB plus clinical follow-up as a gold standard, computed tomographic scans had low sensitivity (20%) for detecting MCC that had spread to the lymph node basin and low specificity for distant disease (only 4 of 21 "positive" scans were confirmed during 6 months of follow-up).

CONCLUSIONS

Sentinel lymph node biopsy detects MCC spread in one third of patients whose tumors would have otherwise been clinically and radiologically understaged and who may not have received treatment to the involved node bed. There was a significant benefit of adjuvant nodal therapy, but only when the SLNB was positive. Thus, SLNB is important for both prognosis and therapy and should be performed routinely for patients with MCC. In contrast, computed tomographic scans have poor sensitivity in detecting nodal disease as well as poor specificity in detecting distant disease.

Impact of sentinel lymph node biopsy in patients with Merkel cell carcinoma: results of a prospective study and review of the literature

PURPOSE

Merkel cell carcinoma (MCC) is the most aggressive of the cutaneous malignancies, showing a propensity to spread to regional lymph nodes (LNs). The aim of this prospective study was to examine the feasibility and clinical impact of sentinel lymph node biopsy (SLNB) in this cutaneous malignancy.

METHODS

The study population comprised 23 patients with stage I MCC (median age 70 years, range 50-85 years). Lymphoscintigraphic mapping with( 99 m)Tc-nanocolloid was performed in all patients. Sentinel lymph nodes (SLNs) were identified, excised and analysed in serial sections by conventional histopathology and cytokeratin-20 immunohistochemistry.

RESULTS

Metastatic disease was determined in the SLNs of 11 patients (47.8%). Elective lymph node dissection (ELND) was performed in eight of these 11 patients, four of whom had additional positive LNs. During follow-up (median 36.1 months, range 3-79 months), seven of the 23 patients (30%) relapsed: four had a local recurrence and three, in-transit metastases. Recurrence developed in two SLN-negative patients with local LN metastases and in one SLN-positive patient with distant metastases. This patient died, representing the only tumour-related death in our sample. Median survival was 49.1 and 35.5 months for SLN-negative and SLN-positive patients, respectively. This difference was not statistically significant (p=0.3452).

CONCLUSION

SLNB allows for exact nodal staging in patients with MCC. Whether additional ELND is of further benefit remains unclear.

Early experience with sentinel lymph node mapping for Merkel cell carcinoma

Merkel cell or cutaneous neuroendocrine carcinoma is a malignant tumor with a propensity toward local and systemic recurrence. A new surgical technique, intraoperative lymphatic mapping and selective sentinel lymph node dissection (SSLND), has been demonstrated to have a high predictive value for the detection of metastatic disease in the regional lymphatic basin in cutaneous melanoma. The use of this technology may be particularly useful to accurately stage patients with Merkel cell carcinoma (MCC) because this tumor has a frequent propensity toward regional nodal metastases. Intraoperative lymphatic mapping and SSLND were performed on 6 patients with biopsy-proven MCC. Three patients with MCC had positive disease in the sentinel lymph node(s). SSLND is a feasible technique with minimal procedural morbidity to detect clinically occult disease in patients with MCC.

Candidate???s Thesis: The Application of Sentinel Node Radiolocalization to Solid Tumors of the Head and Neck: A 10-Year Experience

OBJECTIVES/HYPOTHESIS

The goals of the research study were to develop an easily mastered, accurate, minimally invasive technique of sentinel node radiolocalization with biopsy (SNRLB) in the feline model; to compare it with blue-dye mapping techniques; and to test the applicability of sentinel node radiolocalization biopsy in three head and neck tumor types: N0 malignant melanoma, N0 Merkel cell carcinoma, and N0 squamous cell carcinoma.

STUDY DESIGN

Prospective consecutive series studies were performed in the feline model and in three head and neck tumor types: N0 malignant melanoma (43 patients), N0 Merkel cell carcinoma (8 patients), and N0 squamous cell carcinoma (20 patients).

METHODS

The technique of sentinel node radiolocalization with biopsy was analyzed in eight felines and compared with blue-dye mapping. Patterns of sentinel node gamma emissions were recorded. Localization success rates were determined for blue dye and sentinel node with radiolocalization biopsy. In the human studies, all patients had sentinel node radiolocalization biopsy performed in a similar manner. On the morning of surgery, each patient had sentinel node radiolocalization biopsy of the sentinel lymph node performed using an intradermal or peritumoral injection of technetium Tc 99m sulfur colloid. Sentinel nodes were localized on the skin surface using a handheld gamma detector. Gamma count measurements were obtained for the following: 1) the "hot" spot/node in vivo before incision, 2) the hot spot/node in vivo during dissection, 3) the hot spot/node ex vivo, 4) the lymphatic bed after hot spot/node removal, and 5) the background in the operating room. The first draining lymph node(s) was identified, and biopsy of the node was performed. The radioactive sentinel lymph node(s) was submitted separately for routine histopathological evaluation. Preoperative lymphoscintigrams were performed in patients with melanoma and patients with Merkel cell carcinoma. In patients with head and neck squamous cell carcinoma, the relationship between the sentinel node and the remaining lymphatic basin was studied and all patients received complete neck dissections. The accuracy of sentinel node radiolocalization with biopsy, the micrometastatic rate, the false-negative rate, and long-term recurrence rates were reported for each of the head and neck tumor types. In the melanoma study, the success of sentinel node localization was compared for sentinel node radiolocalization biopsy, blue-dye mapping, and lymphoscintigraphy. In the Merkel cell carcinoma study, localization rates were evaluated for sentinel node radiolocalization biopsy and lymphoscintigraphy. In the head and neck squamous cell carcinoma study, the localization rate of sentinel node radiolocalization biopsy and the predictive value of the sentinel node relative to the remaining lymphatic bed were determined. All results were analyzed statistically.

RESULTS

Across the different head and neck tumor types studied, sentinel node radiolocalization biopsy had a success rate approaching 95%. Sentinel node radiolocalization biopsy was more successful than blue-dye mapping or lymphoscintigraphy at identifying the sentinel node, although all three techniques were complementary. There was no instance of a sentinel node-negative patient developing regional lymphatic recurrence. In the head and neck squamous cell carcinoma study, there was no instance in which the sentinel node was negative and the remaining lymphadenectomy specimen was positive.

CONCLUSION

In head and neck tumors that spread via the lymphatics, it appears that sentinel node radiolocalization biopsy can be performed with a high success rate. This technique has a low false-negative rate and can be performed through a small incision. In head and neck squamous cell carcinoma, the histological appearance of the sentinel node does appear to reflect the regional nodal status of the patient.

Feasibility of preoperative lymphoscintigraphy for identification of sentinel lymph nodes in patients with conjunctival and periocular skin malignancies

PURPOSE

To determine the feasibility of preoperative lymphoscintigraphy for identification of sentinel lymph nodes (SLNs) in patients with conjunctival and periocular skin tumors and to determine the patterns of lymphatic drainage from such tumors.

METHODS

We retrospectively reviewed the records of all patients with biopsy-confirmed conjunctival and periocular skin malignancies who underwent lymphoscintigraphy with or without SLN biopsy between January 1999 and June 2000. Patients underwent lymphoscintigraphy with 0.3 to 1 mCi of technetium Tc-99m sulfur colloid in a volume of either 0.2 mL or 1 mL. Images were taken as soon as the first SLNs were detected through the camera and every 15 minutes thereafter. Intraoperative mapping and SLN biopsy was performed 1 to 2 days after lymphoscintigraphy unless the patient refused or there were medical contraindications to the procedure.

RESULTS

The study included 7 patients with malignant melanoma of the conjunctiva or periocular skin and 1 patient with Merkel cell carcinoma of the eyelid. On lymphoscintigraphy, at least 1 SLN was identified in 7 of the 8 patients. Although all lesions located in the lateral half of the ocular adnexa drained to at least one SLN in the parotid (preauricular) area, there was some variability in the drainage patterns of lesions located in the medial half of the ocular adnexa. A smaller injection volume (0.2 mL) was adequate for detecting the nodes draining the area of injection and led to less spread of technetium to the surrounding areas. Six patients underwent SLN biopsy. In all but one, the nodes identified during surgery corresponded with those visualized on lymphoscintigraphy.

CONCLUSIONS

Preoperative lymphoscintigraphy successfully identifies SLNs in most patients with conjunctival and periocular skin malignancies. Smaller injection volumes (0.2 mL) appear to be adequate for identification of the sentinel nodes and lead to less spread to surrounding tissues.

Discordant lymphatic drainage patterns revealed by serial lymphoscintigraphy in cutaneous head and neck malignancies

BACKGROUND

We analyzed the variability and accuracy of sentinel lymph node (SLN) identification by lymphoscintigraphy performed preoperatively and repeated on the day of operation in patients with melanoma or Merkel cell cancer.

METHODS

Twenty-five prospectively studied patients had lymphoscintigraphy prior to and on the day of operation. Discordance between lymphoscintograms was defined as change in location of SLN or failure to identify a SLN by one of the studies.

RESULTS

In 22 of 24 assessable cases (92%), SLNs were excised. Preoperative lymphoscintigraphy was correct in 19 of 22 (86%) cases. Day of operation lymphoscintigraphy was correct in 20 of 22 (91%) cases. SLN location was as classically described in 24 of 25 (96%) cases. Discordance between lymphoscintigraphy studies was 32% (8/25 patients). Half with discordant migration (8%) yielded metastases in basins not identified by day of operation lymphoscintigraphy but demonstrated by preoperative lymphoscintigraphy.

CONCLUSIONS

Head and neck lymphatic drainage patterns not only vary between patients but also can vary with time for a single patient.

Radiolocalization of the sentinel lymph node in Merkel cell carcinoma: a clinical analysis of seven cases

Merkel cell carcinoma (MCC) is a rare cutaneous skin lesion with a variable but often aggressive clinical course. Patient survival correlates with nodal status and the presence of distant metastases. The histologic status of the sentinel lymph node consistently correlates with the incidence of regional lymphatic metastases in other dermal malignancies. The technique of radiolocalization and surgical resection of the sentinel lymph node using an intraoperative gamma probe is used to guide clinical management in these patients. We report on seven cases of MCC managed utilizing this technique. Four patients had negative sentinel nodes and no other nodal disease at completion lymphadenectomy (n = 2) or clinical follow-up (n = 2) and currently remain disease free. Two patients had a positive sentinel node but no other positive lymph nodes at completion lymphadenectomy; one of them developed regional recurrence. One patient with a positive sentinel node and six additional positive nodes developed extensive nodal disease and systemic recurrence during radiotherapy and expired of MCC. Our results suggest that the sentinel node was identified and removed successfully using radiolocalization making this technique useful in the staging and therapy of patients with MCC.

Applicability of the sentinel node technique to Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) resembles malignant melanoma in several ways. Both are cutaneous lesions of the same embryonic origin. Both have an unpredictable biologic behavior, early regional lymph node involvement, early distant metastases, and high recurrence rate.

OBJECTIVE

To apply the sentinel node technique described for melanoma to MCC in light of the common biologic features of these two tumors.

METHODS

Preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and sentinel node biopsy and frozen section histology were performed to guide the surgical treatment of three patients with MCC.

RESULTS

Application of this approach in patients with MCC is feasible, reproducible, and seems reliable.

CONCLUSION

The use of the sentinel node technique for MCC will reduce the number of unnecessary lymphadenectomies, will enable identification of microscopic metastases to lymph nodes, and will improve the stratification and accrual of patients into adjuvant treatment protocols. It may even lead to a survival benefit.

Indium-111 octreotide scintigraphy of Merkel cell carcinomas and their metastases

BACKGROUND

Somatostatin receptor scintigraphy (SRS) may be of interest for staging Merkel Cell Carcinoma (MCC). This study was undertaken to evaluate the sensitivity and specificity of SRS and to determine its role compared to conventional investigations.

PATIENTS AND METHODS

From 1993 to December 2000, 20 patients (10 females and 10 males, aged from 38 to 88, mean 66 years) were included prospectively. At the time of SRS: 12 patients had been diagnosed as having stage I disease, 6 stage II and 4 stage III. Two patients had two SRS studies during the course of their disease. SRS was performed with Indium-111 pentetreotide (Octreoscan), a radiolabelled somatostatin analogue. Patients were treated according to the clinical stage. A regular follow-up was scheduled every three months.

RESULTS

SRS depicted stage I and II MCC tumour sites with an overall sensitivity of 78% (95% confidence interval (CI): 40%-97%) and a specificity of 96% (81%-100%). The histopathological diagnosis was used as the gold standard. Sites visualised by SRS were compared to those detected with conventional modalities and to follow-up data for all stages: SRS visualised four out of five primary tumour sites, six out of eight lymph node sites, no skin metastases (14 sites in 2 patients), two out of three thoracic metastases and zero out of two hepatic metastases. SRS did not influence treatment decision-making in any of the cases.

CONCLUSIONS

Although SRS seems highly specific in MCC and could be of help in difficult cases, it cannot be recommended for routine evaluation.

Merkel cell carcinoma: CT findings in 12 patients

OBJECTIVE

The purpose of this report is to determine CT imaging findings in patients with Merkel cell carcinoma.

MATERIALS AND METHODS

Fifty-three CT scans in 12 patients with biopsy-proven Merkel cell carcinoma were retrospectively reviewed with regard to size, location, and attenuation of primary skin lesions and visceral and lymph node metastases. Findings that were present in 12 patients form the basis of this report.

RESULTS

Primary skin lesions were manifested on CT scans in four patients as cutaneous nodules that were hyper- or isodense in relation to muscle. Sites of metastases included regional lymph nodes (n = 6), distant lymph nodes (n = 11), the liver (n = 3), and subcutaneous fat (n = 4). We also found metastases in the mediastinum, the peritoneum, the adrenal gland, and the lung. Usually nodal and subcutaneous metastases were slightly hyperdense. Subcutaneous linear stranding was associated with the lesions.

CONCLUSION

CT is useful in the staging of Merkel cell carcinoma.

Lymphoscintigraphy with sentinel lymph node biopsy in cutaneous Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare cutaneous malignancy characterized by an aggressive clinical behavior with high rates of locoregional and systemic recurrence. Regional disease and distant metastases are associated with poor prognosis. Despite a predisposition of MCC to spread via the lymphatics, prophylactic lymph node dissection in the absence of clinically apparent lymph node involvement is controversial. The value of lymphoscintigraphy in cutaneous melanoma is established in lesions with ambiguous lymphatic drainage patterns. When used with sentinel lymph node biopsy (SLNB), it can identify subjects with occult regional node metastasis. The authors present 2 patients with MCC who underwent regional node staging with lymphoscintigraphy-directed SLNB. Both patients had sentinel nodes that were positive for metastatic disease. In patients with MCC, minimally invasive regional node staging SLNB may be useful in limiting the sequelae of routine lymphadenectomies. Whether early identification and treatment of patients with occult regional node disease can influence survival in MCC is not known.

Complete spontaneous regression in Merkel cell carcinoma

Merkel cell carcinoma is a rare, aggressive, cutaneous malignancy of the elderly with a generally poor prognosis. Like all skin cancers, its incidence is rising. A few reports of spontaneous regression have been published. The case of a 67-year-old female patient who presented with a cheek Merkel cell carcinoma is described. Following biopsy it underwent complete regression with no evidence of residual tumour in the excision specimen taken seven weeks later. The current knowledge of Merkel cell carcinoma and the other cases of spontaneous regression described in the literature are reviewed.

Lymphatic mapping and sentinel node biopsy in Merkel's cell carcinoma

AIM

The purpose of this study was to determine the predictive value of lymphatic mapping with selective lymphadenectomy in patients with Merkel's cell carcinoma.

METHODS

Eight patients with biopsy proven Merkel's cell carcinoma underwent sentinel node biopsy. Lymphoscintigraphy was performed the day before surgery following intradermal injection of 74-111MBq of 99mTc-nanocolloid divided into four doses around the biopsy scar. Dynamic and static images were obtained.

RESULTS

At least one sentinel node was visualized in all patients. The sentinel node was intra-operatively identified with the aid of a hand-held gamma probe in all cases and patent blue dye in six out of eight cases. During surgery, all sentinel nodes were successfully harvested. Metastatic cell deposits were subsequently identified in three patients (37.5%) and they underwent regional lymphadenectomy. No additional involved lymph nodes were identified. No recurrence has been reported in a median follow-up of 4.6 years (range: 8 months-10 years).

CONCLUSIONS

In conclusion, sentinel node biopsy in patients with Merkel's cell carcinoma appears to be a reliable staging technique.

Somatostatin analogue scintigraphy in Merkel cell tumours

BACKGROUND

Merkel cell tumours are rare neoplasms of the skin with frequent regional and distant metastases. Scintigraphy with the radiolabelled somatostatin analogue octreotide is a possible method for in vivo localization of the primary tumour and its metastases.

OBJECTIVES

To estimate the diagnostic value of indium (111) -octreotide scintigraphy (Octreoscan in detecting metastases.

METHODS

Scans of 11 patients with Merkel cell carcinoma were evaluated, in whom scintigraphy was performed in addition to the conventional investigations, chest X-ray, ultrasonography and computed tomography (CT).

RESULTS

In four cases metastases were found both by scintigraphy and by conventional methods; two investigations showed a suspicious accumulation of radioactivity on scintigraphy that could not be confirmed by CT and clinical progression. In three cases CT-verified metastases were not found by scintigraphy. Two patients were found to be tumour free, i.e. free of metastases by scintigraphy and conventional methods, indicating true-negative results.

CONCLUSION

These data confirm that scintigraphy with the radiolabelled somatostatin analogue octreotide is not clinically helpful in detecting metastases from Merkel cell carcinoma. In this relatively small sample the method generated false-positive or false-negative results in five of 11 cases.

Merkel cell carcinoma: two case reports focusing on the role of fluorodeoxyglucose positron emission tomography imaging in staging and surveillance

BACKGROUND

Merkel cell carcinoma (MCC) is a rare skin neuroendocrine carcinoma frequently occurring in the head and neck area. It is known for being a locally aggressive disease with a high incidence of regional and distant metastases. Accurate initial staging and close surveillance are critical in the management of the disease.

METHODS AND RESULTS

Two cases of MCC are reported in which fluorine-18-fluorodeoxyglucose positron emission tomography (FDG PET) imaging has been beneficial in directing management and predicting clinical course. Pretreatment FDG PET scans detected metastatic disease in subcentimeter lymph nodes that were not appreciated in initial computed tomography images. Posttreatment FDG PET scans predicted response to therapy with the level of FDG uptake correlating in both areas of complete response to treatment and areas of residual diseases. Finally, FDG PET imaging also detected the progression of the disease after initial treatment.

CONCLUSION

FDG PET imaging is a very sensitive modality in staging, assessment of treatment response, and surveillance of MCC. Because of the rarity of MCC, multicenter study is warranted to accumulate enough cases to determine the sensitivity and specificity of FDG PET in staging and surveillance of MCC, and the impact on the management and treatment outcome.

Somatostatin analogue scintigraphy. A simple and sensitive method for the in vivo visualization of Merkel cell tumors and their metastases

BACKGROUND

Trabecular carcinomas of the skin, or Merkel cell tumors, are aggressive neoplasms that tend to occur in sun-exposed skin. These tumors frequently metastasize and, despite therapy, the number of disease-related deaths is high. Ultrastructurally and immunocytochemically, the majority of these tumors have neuroendocrine characteristics. Recently, we described the in vivo visualization of various neuroendocrine tumors after injection of a radiolabeled somatostatin analogue (octreotide). In this study, we report the results of scintigraphy with radioactive-labeled somatostatin analogues in five patients with Merkel cell tumors.

OBSERVATIONS

In all four patients in whom tumor was detected using computed tomographic scanning and ultrasound, the tumor sites were also demonstrated on octreotide scintigrams. In one patient, a tumor with a diameter that was smaller than 0.5 cm could not be detected with octreotide scintigraphy, computed tomography, or ultrasound. Using octreotide scintigraphy we found presumed tumor spots in two patients that were not evident when other techniques were used.

CONCLUSIONS

Octreotide scintigraphy has an equal or even greater sensitivity than computed tomography and ultrasound for detecting Merkel cell tumors and their metastases. Establishing the spread of the disease in this way may ensure an optimal choice of treatment in patients with this type of tumor.

Merkel Cell Carcinoma: Is there a Role for 2-Deoxy-2-[F-18]fluoro-d-glucose-Positron Emission Tomography/Computed Tomography?

PURPOSE

2-Deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is becoming widely available as a powerful imaging modality, combining the ability to detect active metabolic processes and their morphologic features in a single study. The role of FDG-PET/CT is proven in lymphoma, melanoma, colorectal carcinoma, and other cancers. However, there are rare malignancies such as Merkel cell carcinoma that can potentially be evaluated with PET/CT. We were therefore prompted to review our experience with FDG-PET/CT in the management of patients with Merkel cell carcinoma.

PROCEDURES

This is a retrospective case series of six patients with Merkel cell carcinoma, 58-81 years old (average 69 +/- 8.3), who had whole-body PET/CT at our institution from January 1st, 2003 to August 31st, 2005. Two patients were women and four were men. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed.

RESULTS

Twelve examinations were acquired for the six patients (one patient had six PET/CT, one patient had two PET/CT, and four patients had one PET/CT). The injected FDG doses ranged 381.1-669.7 MBq (average 573.5 +/- 70.3). Four patients had the PET/CT as part of initial staging, and two patients had the exam for restaging (after surgery and XRT). A total of six Merkel lesions (pancreas, adrenal, lip, submandibular lymph nodes, cervical lymph nodes, and parapharyngeal soft tissue) were identified in three patients and confirmed on histopathological examination. The FDG uptake in these areas was intense, with maximum standardized uptake value (SUVmax) values of 5-14 (average 10.4 +/- 3.8). In one patient, the PET/CT scan identified abnormal focal distal sigmoid uptake that was biopsied and diagnosed as adenocarcinoma. Two patients had negative scans and had no clinical evidence of disease on follow-up office visits (up to one year after PET/CT).

CONCLUSIONS

This case series suggests that FDG-PET/CT may have a promising role in the management of patients with Merkel cell carcinoma.

Magnetic resonance imaging appearance of metastatic Merkel cell carcinoma to the sacrum and epidural space

Merkel cell carcinoma (MCC) is a rare malignant tumor of the skin and often is diagnosed histologically as lymphoma, melanoma and even metastatic small cell carcinoma of the lung (SCCL). Classified as a neuroendocrine tumor, clinically it originates in the head and neck region and may present with metastatic disease at the time of presentation [1]. Osseous involvement in the past has been described to involve regional facial bones only. We present the first reported MRI findings of distant osseous metastasis from a Merkel cell carcinoma to the lumbosacral spine with associated soft tissue and epidural involvement. Appropriate treatment and patient survival depend on prompt diagnostic imaging for establishment of metastatic disease. Previous reports have advocated CT for diagnosis and staging of distant metastases [2,3]. When spinal involvement is suspected, MRI may be a more suitable modality for assessment of the epidural space and appropriate staging and follow-up in such cases.

Lymphatic mapping for staging of head and neck cancer

Lymphatic mapping with sentinel lymph node (SLN) biopsy can accurately stage the nodal basins in patients with melanoma of the trunk and extremities and has become a routine, well-accepted diagnostic method for melanoma at these anatomic locations. Melanoma of the head and neck (16% of all cases of melanoma) is complex and difficult to manage because of the rich abundant interlacing lymphatic drainage patterns, as well as watershed areas, which can lead to unusual and unexpected drainage patterns. Radioguided surgery in combination with blue dye facilitates localization of the SLN in the head and neck; however, this type of radioguided surgery is an evolving technique of some difficulty and thus requires careful coordination among the surgeon, nuclear medicine physician, and pathologist. Applications of this technique to other sites in the head and neck are currently being investigated for conditions including squamous cell carcinoma (SCC) of the oral cavity, thyroid cancer, and Merkel cell cancer. More studies of patients with head and neck cancer are needed--and technical issues must be resolved--before radioguided surgery can be recommended as the standard of care for these patients.

Incidence of nonlocalization of sentinel lymph nodes using preoperative lymphoscintigraphy in 74 consecutive head and neck melanoma and Merkel cell carcinoma patients

INTRODUCTION

Lymphatic drainage pathways in the head and neck region are more variable than in any other location of the body. Occasionally, head and neck lymphoscintograms fail to identify a definitive lymphatic drainage pattern, making preoperative and intraoperative identification of sentinel nodes very difficult. The purpose of this study was to determine the incidence of nonlocalization on lymphoscintigraphy of sentinel nodes in patients with head and neck cutaneous malignancies.

METHODS

A retrospective chart review was conducted of a single surgeon's (WKS) 135 consecutive head and neck melanoma and Merkel cell cancer patients from August 1997 to August 2002. In all cases. technetium-99m sulfur colloid was the radioactive tracer used by the nuclear medicine department to perform the lymphoscintograms.

RESULTS

Of the 135 patients, 74 underwent preoperative lymphoscintigraphy in preparation for performing a sentinel lymph node biopsy. Of these 74 patients, 5 (6.8%) were found to have nonlocalization of a sentinel node(s). Of the 5 patients who failed to localize, 3 had primary lesions near the midline scalp, while 2 had primary lesions located on the cheek. Two of the 5 patients underwent reinjection of the radioisotope by the treating surgeon (WKS) but failed to further localize the radiotracer. All 5 patients went on to have wide local excision of the primary cancer on the day of the lymphoscintogram, as well as undergoing intraoperative examination of all head and neck nodal basins with a handheld gamma detector. No focal areas of radiation were identified and no lymph nodes were biopsied. To date, 1 patient has developed distant metastases and has succumbed to her disease. The remaining 4 patients are free of disease.

CONCLUSION

In a series of 135 consecutive patients with head and neck cutaneous malignancies, 74 of whom were treated with preoperative lymphoscintograms, a nonlocalization rate of 6.8% was found. This is a significant rate of nonlocalization and reflects either the inherent difficulty in imaging the head and neck region and/or the possible rapid rate of dye washout via multiple lymphatic drainage pathways that exist in this location.

Merkel cell carcinoma of the external auditory canal invading the intracranial compartment

PURPOSE

To report an unusual case of an intracranial extension of Merkel cell carcinoma originating in the external ear canal and causing neurological deficits.

CASE REPORT

An 86-year-old woman, with a 16-month history of an external auditory canal mass, presented with hemiparesis, facial paralysis, and obtundation. Radiographic images showed an intracranial mass extending into the petrous bone.

METHOD

The patient had a craniotomy for intracranial tumor resection with concurrent mastoidectomy for facial nerve decompression and obtundation and hemiparesis were resolved. Residual tumor was subsequently treated with adjuvant radiation therapy, and facial nerve function consequently improved.

CONCLUSION

Merkel cell tumors rarely invade the intracranial compartments. Residual tumor and neurological deficits may respond to adjuvant radiation therapy.

Color Doppler Sonography of Merkel Cell Carcinoma

We illustrate the color Doppler sonographic findings in primary cutaneous Merkel cell carcinoma. Eight cases (4 female and 4 male; mean age, 75.4 years) were collected. The most common affected regions were the face (63%) and the hip/buttock (25%). The mean transverse diameter and thickness were 21 and 14 mm, respectively. Fifty percent were oval, and 50% were dome shaped. All lesions were hypoechoic, with variable degrees of heterogeneity. All but 2 lesions were poorly defined. An acoustic reinforcement artifact was present in 3 and epidermal thickening in 2. All tumors had prominent and chaotic hypervascularity with arterial vessels (mean peak velocity, 11 cm/s; mean resistive index, 0.57).