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PubMed2006

Metabotropic glutamate receptor antagonists selectively enhance responses of slowly adapting type I mechanoreceptors.

There is evidence that glutamate may participate as a transmitter at the junction between Merkel cells and the nerve terminals of slowly adapting type I (St I) units. We recorded extracellularly from the deep vibrissal nerve of an isolated rat vibrissa preparation in vitro. Five second trapezoid stimulus ramp deflections of the hair shaft were used to evoke responses. We bath-applied two compounds, which we planned would interfere with glutamatergic transmission. (2S)-2-Amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid (LY341495) was used at concentrations up to 100 microM to block all known metabotropic glutamate (mGlu) receptors. The racemic mixture (RS)-4-carboxy-3-hydroxyphenylglycine ((RS)-4C3HPG) was used up to 100 microM to block ionotropic and Group I metabotropic glutamate receptors, and as an agonist at Group II mGlu receptors. Unexpectedly, both compounds had rapid onset excitatory effects on mechanically-evoked responses. (RS)-4C3HPG increased responses, with a mean 146% of control (P < 0.05) in a concentration-dependent manner. LY341495 increased responses, with a mean 128% of control (P < 0.05). With (RS)-4C3HPG in particular, it was noted that the static component (the firing during the last 1 s plateau) was preferentially enhanced relative to the dynamic component (firing during the first 0.5 s). Rapid recovery was seen after wash. Slowly adapting type II units, which have no junctional transmission, were completely unaffected by these compounds up to 200 microM. These results suggest that mGlu receptors play a role in Merkel cell-neurite complex mechanotransduction, although other explanations are considered.

Animals↗
PubMed2002

A study of eleven cutaneous malignant melanomas in adults with small-cell morphology: emphasis on diagnostic difficulties and unusual features.

AIMS: To describe the clinicopathological and immunohistochemical features of cutaneous malignant melanomas with a pure or mixed small-cell pattern in 11 adult patients, and to discuss the diagnostic difficulties encountered. METHODS AND RESULTS: Haematoxylin and eosin-stained sections of each case of cutaneous small-cell malignant melanoma, together with locally recurrent skin lesions and, where available, metastatic deposits, were re-examined. Available immunohistochemical sections were evaluated. Clinical follow-up data were obtained in each case. One patient presented with metastatic disease, the others presented with cutaneous lesions. Suggested initial diagnoses included malignant melanoma, non-Hodgkin's lymphoma, Merkel cell carcinoma and sarcoma. All the tumours were in the vertical growth phase. Nine had a junctional component, often inconspicuous. The lesions showed either a pure small-cell pattern or a mixed pattern with more conventional areas. In one case, there was colonization of a basal cell carcinoma by invasive malignant melanoma. Variable retention of small-cell morphology in local recurrences and metastases was observed, although in some cases more typically pleomorphic cells were present. In the cases tested, there was strong immunostaining for S100 protein and NKI-C3, and variable immunostaining for HMB45 and Melan-A. Non-melanocytic markers were negative. CONCLUSIONS: The possibility of a small-cell malignant melanoma should be considered in the assessment of cutaneous and non-cutaneous small-cell neoplasms. The correct diagnosis requires careful evaluation for junctional activity, melanin production and the use of a panel of melanocytic markers.

Adult↗
PubMed2003

Functional consequences of the glycophenotype of squamous epithelia--practical employment.

Squamous epithelia represent a morphologically and differentiation-dependent stratified tissue. The stem cells are located in the bulge region of hair follicles or in the basal layer of interfollicular epidermis and in the limbus of the cornea. This article summarizes the data about the glycobiological aspects of squamous epithelia cell differentiation under physiological as well as pathological conditions in relation to the function of this epithelial tissue. The entries about the LC, Merkel cells and melanocytes are also mentioned. The employment of the described data in the diagnostics of carcinomas derived from this type of epithelium as well as in the cell therapy of skin defects are shown.

Agglutinins↗
PubMed1991

[Lymphoepithelioma-like carcinoma of the skin].

Lymphoepithelioma-like carcinoma of the skin (LECS) is a rare cutaneous tumour with histological features resembling those of Epstein-Barr virus-induced nasopharyngeal carcinoma. An LECS tumour may mimic lymphoid follicles in its composition. Its distinct histological pattern, however, is based on syncytial nests and cords of large pale-staining epithelial tumour cells surrounded by a dense lymphoplasmacytic infiltrate. Tumour cells show conspicuous vesicular nuclei with delicate chromatin and few prominent nucleoli. Histological differential diagnosis must include malignant lymphomas, Merkel cell tumour, squamous cell carcinoma and cutaneous metastasis of lymphoepithelioma. Immunostaining with anticytokeratin antibodies is highly significant in the differential diagnosis. Histological and immunohistological findings in an LECS removed from the upper lip of a 56-year-old women are reported. Serologic investigations did not indicate EBV-associated tumour growth.

Carcinoma, Merkel Cell↗
PubMed2000

A case of localized follicular hamartoma: an ultrastructural and immunohistochemical study.

We report the case of a 22-year-old woman with a nevoid plaque that we termed localized follicular hamartoma. The plaque was noticed at puberty on a unilateral site of the face and scalp. Clinically, it revealed numerous, skin-colored to light brown papules alone and in groups, occasionally bearing a single hair. Histologically, branched epithelial nests of squamoid and/or basaloid cells were revealed in connection with the interfollicular epidermis and the upper portions of hair follicles, of which the lower portions showed normal structures. Immunohistochemically, the epithelial nests showed the keratin expression consisted with that of the infundibular epithelium. S-100-positive cells were found in the epithelial nests and the stroma. Factor XIIIa-positive dendritic cells were numerous in adjacent to the epithelial nests. Ultrastructurally, immature melanocytes with a small number of premelanosomes and Merkel cells were found in the nests. Stromal dendritic cells showed the adherent features of the cytoplasmic processes to anchoring fibrils or basal lamina of the epithelial nests. From these findings, our case is a hamartoma, which seems to be an abortive growth of secondary hair germs with a limited differentiation to the upper follicular portion.

Adult↗
PubMed1993

Salvage treatment after r-interferon alpha-2a in advanced neuroendocrine tumors.

The use of inteferon (IFN) in neuroendocrine advanced tumors has achieved control of hormonal symptoms but low objective tumor response rate. In patients resistant to, or failing on, IFN a second line treatment may be required. Seventeen patients having received recombinant IFN alpha-2a as last treatment entered the study. There were 12 carcinoids, 3 medullary thyroid carcinomas, one Merkel cell carcinoma, and one neuroendocrine pancreatic tumor. Two different treatments were used: one radiometabolic therapy with metaiodobenzylguanidine (MIBG) in 3 patients with high MIGB uptake and one polychemotherapy regimen, including streptozotocin 500 mg/m2 intravenously days 1, 2, 3 and epirubicin 75 mg/m2 intravenously day 1, in the remaining 14 patients. Stable disease with relief of symptoms and tumor marker reduction was obtained in two patients receiving MIGB therapy, whereas the third patient had progressive disease. In the chemotherapy group only one partial response was obtained and neither tumor marker reduction nor subjective improvement were seen. Our second-line treatment was not especially effective but may be considered for rapidly progressive and/or symptomatic disease. The radiometabolic therapy appears promising in symptomatic patients with small tumor burden whereas our chemotherapy regimen appears ineffective.

3-Iodobenzylguanidine↗
PubMed1996

Ontogeny of the cutaneous sensory organs.

The ontogeny of cutaneous sensory nerve organs is described in higher vertebrates, and includes the lamellated corpuscles of Meissner, Pacini and Herbst, and the Merkel cell-neurite complex with bird Merkel and Grandry corpuscles, and mammalian Merkel cells. The main common feature is that for most corpuscles there is an inside-out order of assembly around the nerve ending which is present from the beginning of end-organ ontogeny. The exception is the mammalian Merkel cell which is present in the epidermis before the entrance of nerve fibers, and could play a promotional role in the development of skin innervation. The developmental origin of Herbst and Merkel corpuscles in birds is reported as demonstrated using embryological experiments with cell markers. Conclusions are that inner bulb cells of Herbst corpuscles and bird Merkel cells are of neural crest origin, whereas other cells (inner space and capsular cells for Herbst corpuscle and capsular cells for Merkel corpuscles) are provided by the local mesenchyme. The question of the ontogeny of mammalian Merkel cells is discussed in relation to the two debated hypothesis of epidermal and neural crest origins. Morphogenetic interactions during the development of cutaneous sensory end organs are also discussed.

Animals↗
PubMed1996

Cutaneous overexpression of NT-3 increases sensory and sympathetic neuron number and enhances touch dome and hair follicle innervation.

Target-derived influences of nerve growth factor on neuronal survival and differentiation are well documented, though effects of other neurotrophins are less clear. To examine the influence of NT-3 neurotrophin overexpression in a target tissue of sensory and sympathetic neurons, transgenic mice were isolated that overexpress NT-3 in the epidermis. Overexpression of NT-3 led to a 42% increase in the number of dorsal root ganglia sensory neurons, a 70% increase in the number of trigeminal sensory neurons, and a 32% increase in sympathetic neurons. Elevated NT-3 also caused enlargement of touch dome mechanoreceptor units, sensory end organs innervated by slowly adapting type 1 (SA1) neurons. The enlarged touch dome units of the transgenics had an increased number of associated Merkel cells, cells at which SA1s terminate. An additional alteration of skin innervation in NT-3 transgenics was an increased density of myelinated circular endings associated with the piloneural complex. The enhancement of innervation to the skin was accompanied by a doubling in the number of sensory neurons expressing trkC. In addition, measures of nerve fibers in cross-sectional profiles of cutaneous saphenous nerves of transgenics showed a 60% increase in myelinated fibers. These results indicate that in vivo overexpression of NT-3 by the epidermis enhances the number of sensory and sympathetic neurons and the development of selected sensory endings of the skin.

Animals↗
PubMed2000

CD99 and cytokeratin-20 in small-cell and basaloid tumors of the skin.

Although it is classically a deep soft-tissue tumor of childhood, primitive neuroectodermal tumor (PNET) can occur at any age and may occasionally involve cutaneous sites. Merkel cell carcinoma (MCC) and basaloid neoplasms of cutaneous adnexa are the principal diagnostic alternatives to that tumor. The common expression of CD99 in PNET and cytokeratin-20 (CK20) in MCC suggests that these markers may be of value in this diagnostic setting, but they have not been rigorously examined in other small-cell and basaloid lesions of the skin. Accordingly, we evaluated CD99 and CK20 reactivity in formalin-fixed, paraffin-embedded sections of 30 MCC, five cutaneous metastases of pulmonary small-cell neuroendocrine carcinomas, 10 primary cutaneous adnexal carcinomas with basaloid features, 18 benign basaloid adnexal neoplasms of the skin (nine spiradenomas and nine cylindromas), and two cutaneous PNETs, using a standard immunohistologic technique and microwave-mediated epitope retrieval. Of the 30 MCC, 12 showed crisp membrane staining for CD99. Among the remaining tumors, only the two PNETs were positive for that marker. Although the majority of MCCs did not label for CD99, the pattern of reactivity in positive cases was indistinguishable from that observed in PNETs. Eighteen of 27 MCCs that were stained for CK20 were reactive for that protein, in contrast to metastatic small cell carcinomas, cutaneous PNETs, and appendageal skin tumors, which were uniformly negative for this marker. However, a subset of nine tumors, which were most consistent with MCC on clinical grounds, was CD99 positive and CK20 negative. Hence, reliance on CD99 alone as a diagnostic marker for PNET in this context cannot be recommended. Rather, careful assessment of the clinical presentation, together with extended immunophenotyping that includes other lineage markers and, when possible, cytogenetic analysis for characteristic chromosomal aberrations, remains the best means of separating MCC from PNET. Finally, the lack of CD99 reactivity in basaloid adnexal neoplasms of the skin suggests a utility in their differential diagnosis from cutaneous tumors with neuroendocrine or neuroectodermal differentiation.

12E7 Antigen↗
PubMed2006

Fibroepithelioma of pinkus.

An 88-year-old woman presented with an 8-year history of a slowly enlarging growth on the suprapubic area. A shave excision of this lesion demonstrated fibroepithelioma of Pinkus (FEP). Fibroepithelioma of Pinkus is an indolent growing tumor that traditionally has been classified as a variant of the basal cell carcinoma. More recent evidence favors the classification of FEP as a variant of trichoblastoma. In this case report, we identified a large FEP with benign histologic features suggestive of a follicular origin as demonstrated in part by CK 20 staining and the presence of scattered Merkel cells within the tumor. The pathogenesis of FEP remains enigmatic, and the genetic basis has yet to be fully elucidated. Complete surgical resection is considered curative.

Aged, 80 and over↗
PubMed2003

Developmental expression pattern of monoamine oxidases in sensory organs and neural crest derivatives.

Serotonin (5-HT) has been shown to act as a morphogen in craniofacial and heart development and in the migration of neural crest derivatives. Some of these structures are capable of capturing 5-HT during development, but nothing is known about the localization of the main monoamine degradation enzymes, monoamine oxidase (MAO) A and B, in these developing tissues. We generated a highly specific antibody to MAOB; immunoreactivity is entirely abolished in brain extracts or brain sections of mice lacking MAOB. From the use of this antibody and specific riboprobes, we report that MAOB is expressed early in a variety of neural crest derivatives, in facial sensory organs, and in the heart. From E11.5 to P0, MAOB was found to be strongly expressed in the following neural crest derivatives: the aorta, cranial mesenchyme (developing bones, sensory neurons of the cranial ganglia, cartilages, thyroid, and striate muscles), dental mesenchyme, several soft palate derivatives, and boundary cap cells (E11.5-P4). Boundary cap cells contribute to the formation of nerve exit-entry points between the central and the peripheral nervous systems. Several facial sensory organs also contained MAOB mRNA, protein, and activity. High MAOB expression was noted in the olfactory placode, the dorsal part of the olfactory epithelium, the olfactory nerve layer (probably the ensheathing glia), the cochlear ganglionic cells, the taste buds, and the Merkel cells in the vibrissae follicles. Finally, we found that MAOB is massively expressed in the pharyngeal organ, heart, liver, and mast cells. In contrast, MAOA expression was restricted to the sympathetic ganglia and to the meningeal and capillary blood vessels. The pattern of MAOB expression generally matched the previously reported patterns of expression of the plasma 5-HT transporter expression or of the histamine biosynthetic enzyme L-histidine decarboxylase, suggesting a role for MAOB in fine regulation of the levels of 5-HT and histamine in the developing embryo.

Aging↗
PubMed1988

Ultrastructure of taste cells and synapses in the mudpuppy Necturus maculosus.

Taste buds in the mudpuppy Necturus maculosus were examined with electron microscopy. Three cell types (dark, light, and basal) were identified and reconstructed from serial thick sections. Dark and light cells extend from the basal lamina to the surface of the tongue. The apical process of the dark cells was usually quite lamellar when viewed in cross section, in contrast to light cells, whose apical process appeared more cylindrical. Basal cells are situated at the base of the bud and do not extend processes to the surface of the tongue. The cytoplasm of basal cells contains numerous clear and dense-cored vesicles. Small, spinelike processes (2-3 microns in length) project outward from the basal cells into the cytoplasm of the surrounding tast receptor cells. Morphologically, basal cells in mudpuppy taste buds resemble Merkel cells. Unmyelinated afferent nerve fibers enter the taste bud at the base and course through the lower portion of the bud. Synapses were found between taste receptor cells and nerve fibers, between basal cells and nerve fibers, and between basal cells and taste receptor cells. Over 65% of the synapses observed in the mudpuppy taste bud involved the basal cell. These findings suggest that basal cells play some role in chemosensory signal processing or integration of the taste response.

Animals↗
PubMed2003

Cutaneous metastasis of neuroendocrine carcinoma of the larynx: report of a case.

BACKGROUND: Cutaneous metastasis from neuroendocrine carcinomas of visceral origin is rarely described in indexed literature. The primary sites of origin include: lung (Wick et al., J Am Acad Dermatol 1985; 13: 134), larynx (Zambruno et al., Ann Dermatol Venereol 1989; 116: 855; Schmidt et al., J Laryngol Otol 1994; 108: 272; Guerzider et al., Ann Pathol 1991; 11 (4): 253), mediastinum (Yoshimasu et al., J Dermatol 2001; 28 (3): 168), uterus (Fogaca et al., J Cutan Pathol 1993; 20: 455), and thymus (Wick et al., J Am Acad Dermatol 1985; 13: 134). METHODS: In this report, the authors present the clinical, histological, immunohistochemical, and ultrastructural characteristics of secondary skin localizations of a neuroendocrine laryngeal tumor that occurred in a 61-year-old man. The complete follow up of the case is described and a brief revision of the terminology and classification of neuroendocrine neoplasms of the larynx is discussed, since a significant relationship exists between the degree of differentiation and biological behavior. RESULTS: On histological examination, the secondary cutaneous localization appeared to be more dedifferentiated compared to the primary tumor. The immunohistochemical patterns of reactivity were similar in both neoplasms, showing expression of neuroendocrine and epithelial markers. CONCLUSIONS: An important issue of prognostic significance is to differentiate a cutaneous metastasis of a neuroendocrine carcinoma from the primary small cell-undifferentiated carcinoma of the skin (Merkel cell carcinoma).

Biomarkers, Tumor↗
PubMed2004

Lymphatic density and metastatic spread in human malignant melanoma.

Malignant melanoma (MM), the most common cause of skin cancer deaths, metastasises to regional lymph nodes. In animal models of other cancers, lymphatic growth is associated with metastasis. To assess if lymphatic density (LD) was increased in human MM, and its association with metastasis, we measured LD inside and around archival MM samples (MM, n=21), and compared them with normal dermis (n=11), basal cell carcinoma (BCC, n=6) and Merkel cell carcinoma (MCC), a skin tumour thought to metastasise through a vascular route (MCC, n=6). Lymphatic capillary density (mm(-2)), as determined by immunohistochemical staining with the lymphatic specific marker LYVE-1, was significantly increased around MM (10.0+/-2.5 mm(-2)) compared with normal dermis (2.4+/-0.9 mm(-2)), BCC (3.0+/-0.9 mm(-2)) and MCC (2.4+/-1.4 mm(-2)) (P<0.0001). There was a small decrease in LD inside MM (1.1+/-0.7 mm(-2)) compared with normal dermis, but a highly significant decrease in BCC (0.14+/-0.13) and MCC (0.12+/-2.4) (P<0.01 Kruskal-Wallis). Astonishingly, LD discriminated between melanomas that subsequently metastasised (12.8+/-1.6 mm(-2)) and those that did not (5.4+/-1.1 mm(-2), P<0.01, Mann-Whitney). Lymphatic invasion by tumour cells was seen mainly in MM that metastasised (70% compared with 12% not metastasising, P<0.05 Fisher's Exact test). The results show that LD was increased around MMs, and that LD and tumour cell invasion of lymphatics may help to predict metastasis. To this end, a prognostic index was calculated using LD, lymphatic invasion and thickness that clearly discriminated metastatic from nonmetastatic tumours.

Basal Cell Carcinoma↗
PubMed2002

Oblimersen Bcl-2 antisense: facilitating apoptosis in anticancer treatment.

The components of the apoptotic program are targets for anticancer therapy. Bcl-2 protein inhibits apoptosis and confers resistance to treatment with traditional cytotoxic chemotherapy, radiotherapy, and monoclonal antibodies (mAb). Oblimersen sodium (G3139, Genasense, Genta Inc., Berkeley Heights, NJ) is an antisense oligonucleotide (AS-ON) compound designed to specifically bind to the first 6 codons of the human bcl-2 mRNA sequence, resulting in degradation of bcl-2 mRNA and subsequent decrease in Bcl-2 protein translation. Oblimersen is the first oligonucleotide to demonstrate proof of principle of an antisense effect in human tumors by the documented downregulation of the target Bcl-2 protein. A growing body of preclinical and clinical evidence suggests that oblimersen synergizes with many cytotoxic and biologic/immunotherapeutic agents against a variety of hematologic malignancies and solid tumors. Randomized clinical trials are currently underway to evaluate the efficacy and tolerability of oblimersen in combination with cytotoxic chemotherapy in chronic lymphocytic leukemia, multiple myeloma, malignant melanoma, and non-small cell lung cancer. In addition, nonrandomized trials are under way to evaluate oblimersen in non-Hodgkin's lymphoma, acute myeloid leukemia, and hormone-refractory prostate cancer. Preclinical data also support the clinical evaluation of oblimersen in additional tumor types, including chronic myelogenous leukemia and breast, small cell lung, gastric, colon, bladder, and Merkel cell cancers. Enhancement of the efficacy of anticancer treatments with oblimersen Bcl-2 antisense therapy represents a promising new apoptosis-modulating strategy, and ongoing clinical trials will test this therapeutic approach.

Antineoplastic Agents↗
PubMed1998

Small cell sweat gland carcinoma in childhood.

Sweat gland carcinomas are rare skin tumors that typically occur in older patients. The spectrum of their clinical and pathologic features is broad, and many different types of sweat gland carcinomas have been described, ranging from fairly indolent to highly aggressive neoplasms. We present two cases of sweat gland carcinoma with a predominant small cell morphology. Both tumors occurred in children. One lesion developed in an 8-year-old girl as an asymptomatic papule on her left forearm, which ultimately was evaluated using biopsy because of rapid growth and change in color. The other lesion occurred on the hand of a 12-year-old boy. Both tumors were pandermal and extended into fat. They were composed of monotonous cuboidal cells with scant cytoplasm that formed tubules and grew in anastomosing cords and trabeculae. The tumor cells were immunoreactive for cytokeratins but not for cytokeratin 20. Ultrastructural analysis (available in one case only) showed that the tumor cells lacked neurosecretory granules. This variant of sweat gland carcinoma needs to be distinguished from other small cell neoplasms of the skin, especially Merkel cell carcinoma, its closest mimic.

Biopsy↗
PubMed2002

Thyroid transcription factor-1: a review.

Thyroid transcription factor-1 (TTF-1) is a 38-kd homeodomain containing DNA-binding protein originally identified in follicular cells of the thyroid and subsequently in pneumocytes. This review focuses on the utility of antisera in TTF-1 immunohistochemical staining in the diagnosis of neoplastic conditions. Based on published studies to date, anti-TTF-1 is a very useful reagent in distinguishing pulmonary adenocarcinoma from other primary carcinomas, identifying differentiated thyroid neoplasms, distinguishing mesothelioma from pulmonary adenocarcinoma, and distinguishing small cell carcinoma of the lung from Merkel cell carcinoma. It may also be useful in distinguishing neuroendocrine (NE) tumors of the lung from well-differentiated NE tumors from other sites, such as the intestine.

Biomarkers, Tumor↗
PubMed2006

Lymphatic mapping and sentinel lymphadenectomy for 106 head and neck lesions: contrasts between oral cavity and cutaneous malignancy.

OBJECTIVES: The objectives of this prospective series were to present our results in 106 sequential cases of lymphatic mapping and sentinel lymph node biopsy (SLNB) in the head and neck region and contrast the experience in oral cancer with that for cutaneous lesions. HYPOTHESES: SLNB has an acceptably low complication rate in the head and neck. Lymphatic mapping and gamma probe-guided lymphadenectomy can improve the management of malignancies of the head and neck by more accurate identification of the nodal basins at risk and more accurate staging of the lymphatics. For appropriately selected patients, radionuclide lymphatic mapping may safely allow for minimally invasive sentinel lymphadenectomy without formal completion selective lymphadenectomy. METHODS: One hundred six patients underwent intralesional radionuclide injection and radiologic lymphoscintigraphy (LS) on Institutional Review Board-approved protocols and 103 of these underwent successful SLNB. These included 35 patients with malignant melanoma, 10 cutaneous squamous cell carcinomas, four lip cancers, eight Merkel cell carcinomas, two rare cutaneous lesions, and 43 oral cancers. Mean follow up was 24 months. Patients with oral cavity malignancy underwent concurrent selective neck dissection after narrow-exposure sentinel lymph node excision. In this group, the SLNB histopathology could be correlated with the completion neck specimen histopathology. Patients with cutaneous malignancy underwent SLNB alone and only received regional lymphadenectomy based on positive histology or clinical indications. Data were tabulated for anatomic drainage patterns, complications, histopathology, and patterns of cancer recurrence. RESULTS: Surgical complications were rare. No temporary or permanent dysfunction of facial or spinal accessory nerves occurred with sentinel node biopsy. Lymphatic drainage to areas dramatically outside of the expected lymphatic basins occurred in 13.6%. Predictive value of a negative sentinel node was 98.2% for cutaneous malignancies (based on regional recurrence) and 92% with oral cancer (based on pathologic correlation). Gross tumor replacement of lymph nodes and redirection of lymphatic flow represented a significant technical issue in oral squamous cell carcinoma. Sixteen percent of patients with oral cancer were upstaged from N0 to N1 after extended sectioning and immunohistochemistry of the sentinel node. CONCLUSIONS: LS and SLNB can be performed with technical success in the head and neck region. Complications are minimal. More accurate staging and mapping of lymphatic drainage may improve the quality of standard lymphadenectomy. The potential for minimally invasive surgery based on this technology exists, but there is a small risk of missing positive disease. Whether the failure rate is greater than that of standard lymphadenectomy without gamma probe guidance is not known. New studies need to focus on refinements of technique and validation of accuracy as well as biologic correlates for the prediction of metastases.

Adult↗