[Atypical keloids with an unusual myofibroblastic differentiation in a patient with acne vulgaris]

We present the case of a patient with a discreet acne and multiple keloids in the area of the upper trunk, histologically showing an unusual myofibroblastic differentiation. So far, the clinical course shows a poor response to the treatment, including cryotherapy, intralesional corticosteroid injections, occlusive silicone dressings and dye laser.

Metabolic reprogramming and angiogenesis in primary cutaneous Merkel cell carcinoma: expression of hypoxia-inducible factor-1α and its central downstream factors

BACKGROUND

Metabolic reprogramming and altered gene expression mediated by hypoxia-inducible factors play crucial roles during tumour growth and progression. Nevertheless, studies analysing the expression of hypoxia-inducible factor-1α and its downstream targets in Merkel cell carcinoma (MCC) are lacking but are warranted to shed more light on MCC pathogenesis and to potentially provide new therapeutic options.

OBJECTIVES

To analyse the immunohistochemical expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor-A (referred to as VEGF throughout the manuscript), VEGF receptor-2 (VEGFR-2), VEGF receptor-3 (VEGFR-3), glucose transporter-1 (Glut-1), monocarboxylate transporter 4 (MCT4) and carbonic anhydrase IX (CAIX) in primary cutaneous MCC.

METHODS

The 16 paraffin-embedded primary cutaneous MCCs (Merkel cell polyomavirus (McPyV) positive/negative: 11/5) were analysed by immunohistochemistry, namely HIF-1α, VEGF, VEGFR-2 (KDR), VEGFR-3 (FLT4), Glut-1, MCT4 and CAIX. An established quantification score (QS) was applied to quantitate the protein expression by considering the percentage of positive tumour cells (0: 0%; 1: up to 1%; 2: 2-10%; 3: 11-50%; 4: >50%) in relation to the staining intensity (0: negative; 1: low; 2: medium; 3: strong).

RESULTS

HIF-1α was expressed in all MCCs and predominantly found at the invading edges of tumour margins. The HIF-1α downstream factors Glut-1, MCT4 and CAIX were expressed in 13 of 16 MCC (81%), 14 of 16 MCC (88%) and 16 of 16 MCC (100%), respectively. Interestingly, VEGF and VEGFR-2 were not expressed in tumour cells, whereas VEGFR-3 was expressed in all MCCs. HIF-1α was expressed significantly stronger in McPyV⁺ tumours (QS: 10.36 ± 2.41) than in McPyV^- tumours (QS: 5.40 ± 1.34; P = 0.002). Similarly, VEGFR-3 was also expressed significantly stronger in McPyV⁺ tumours (QS: 10.00 ± 2.52) than in McPyV^- tumours (QS: 5.40 ± 3.43, P = 0.019).

CONCLUSIONS

Our data provide first evidence for a role of HIF-1α in induced metabolic reprogramming contributing to MCC pathogenesis. The metabolic signatures of McPyV⁺ and McPyV^- tumours seem to show relevant differences.

[Multiple eccrine hidrocystomas on the lower forehead and nose of a 60-year-old man]

Multiple eccrine hidrocystomas are benign cystic skin lesions which originate from the sweat gland ducts and typically affect women's midfacial area. Sweating may lead to an increase in size of the translucent papules. In some cases hidrocystomas are associated with other diseases such as Parkinson's disease. Treatment options include laser, topical and systemic anticholinergic drugs (glycopyrrolate, clonidine, atropine, and oxybutynin), whereby therapeutic success is limited in most cases.

Pulmonary, rhino-orbital and cutaneous mucormycosis caused by Rhizomucor pusillus in an immunocompromised patient

The number of patients with haematopoietic malignancies receiving chemotherapy and stem-cell transplantation has increased the incidence of severe opportunistic infections. Systemic fungal infections are of major concern in immunocompromised patients, as these infections are often fatal. We report a case of a patient with acute myeloid leukaemia who developed multiple cutaneous plaques and necrotizing infiltrates in the lungs during chemotherapy. Using real-time PCR on a wax-embedded tissue sample, Rhizomucor pusillus was identified. We provide an overview of the literature on cutaneous mucormycosis and its diagnosis by PCR.

[Perianal streptococcal dermatitis caused by β-hemolytic group G streptococci in two adults]

Perianal streptococcal dermatitis is generally considered a childhood disorder caused by β-hemolytic group A streptococci. It should also be considered in cases of therapy-refractory gluteal erythema in adults. We report two cases of perianal streptococcal dermatitis in adults. In both, the microbiological examination of the skin swabs showed β-hemolytic group G streptococci. Therapy of choice is penicillin.

Reduction of regulatory T cells in skin lesions but not in peripheral blood of patients with systemic scleroderma

OBJECTIVE

To determine the frequency and suppressive capacity of regulatory T cells (T(reg)) and their association with clinical parameters in patients with systemic scleroderma (SSc).

METHODS

Peripheral blood from 25 patients with SSc, 15 patients with localised scleroderma (LS) and 29 healthy controls (HC) was studied. Analysis of CD4(+) forkhead box P3 (Foxp3)(+) and CD4(+)CD25(++)Foxp3(+) T(reg) subpopulations was carried out by flow cytometry and cell proliferation was quantified by (3)H-thymidine incorporation. Quantitative analysis of T(reg) was further performed in skin biopsies from 17 patients with SSc and 21 patients with LS using anti-CD4 and anti-Foxp3 monoclonal antibodies for immunohistochemistry.

RESULTS

The frequency of CD4(+)Foxp3(+) and CD4(+)CD25(++)Foxp3(+) T(reg) in peripheral blood from patients with SSc was not significantly different from that of patients with LS or HC. The suppressive capacity of CD4(+)CD25(++) T(reg) in SSc was also found to be similar to that of HC. Phenotypic and functional data revealed no significant difference between the limited or diffuse form of SSc. Moreover, therapy with bosentan showed no significant effect on the frequency of T(reg) during the course of the disease. However, the frequency of T(reg) in skin lesions from patients with SSc or LS, determined as the percentage of CD4(+) cells expressing Foxp3 in the inflammatory infiltrate, was significantly reduced compared with other inflammatory skin diseases.

CONCLUSION

These results indicate that although the authors found no defect in the frequency or function of peripheral T(reg) subpopulations, the reduction of CD4(+)Foxp3(+) T(reg) in the skin of patients with SSc may be important in the pathogenesis of the disease.

[Solid, asymptomatic nodules on several toes in a child]

The term infantile digital fibromatosis describes a benign tumor of the group of fibromatoses. The prevalence rate is approximately 2.5% of all fibromatoses. The etiopathogenesis of infantile digital fibromatosis is unknown. These tumors can appear already at birth, but usually manifest during the first 3 years of life as solid, pink or skin-colored asymptomatic nodules on one or several fingers or toes. Because of the postoperative recurrence rate of 50-75% and the possibility of spontaneous regression, excision is not recommended according to currently available evidence.

[Acne inversa]

Acne inversa is a chronic inflammatory disease of the hair follicles. It can lead to severe functional and psychological impairment. It is characterized by inflamed painful nodules, abscesses, fistulas and scarring in late stages of the disease. The causes of acne inversa are still not fully understood. Conservative treatment options such as antibiotics may lead to clinical improvement; however they do not produce healing. Therapy of choice, especially in severe forms, is radical wide excision of all affected areas. Despite a variety of treatment options, acne inversa is still a therapeutic challenge.

[Verrucous tumor of the amputation stump]

Epithelioma cuniculatum (EC) belongs to the category of verrucous carcinomas. Invasiveness and rate of metastasis are low, but there is a high risk of local recurrence. In cases of long-standing processes with formation of exophytic, malodorous tumors with jagged edges that do not respond to conventional therapy, consideration should already be given to EC upon visual inspection. The diagnosis is always established by histological examination. The standard treatment of EC is extensive excision of the tumor with micrographic margin control.

The effect of denervation of Merkel cells in cats

The morphology of Merkel cells in sinus hair follicles of the upper lip (vibrissae with a circular blood sinus), and in touch domes of the glabrous skin of the nose, was investigated in cats up to 12 weeks after resection of the infraorbital nerve. Even 12 weeks after denervation there was neither an ultrastructural alteration of Merkel cells nor a reduction of their number in sinus hair follicles. Also in touch domes the Merkel cells did not disappear.

Fatal varicella in an immunocompromised adult associated with a European genotype E2 variant of varicella zoster virus

Varicella zoster virus (VZV) seronegative patients under immunosuppressive therapy are at risk for severe life-threatening varicella. A 25-year-old male patient presented with rash and hepatitis. He had been known to suffer from Crohn's disease and received immunosuppressive treatment with azathioprine. The patient showed dyspnoea, and presented with a generalized rash with vesicular lesions typical for herpesvirus infections. He was started immediately on acyclovir therapy. Varicella infection was determined in this VZV seronegative patient in rash vesicles, blood and tracheal secretions and a high VZV viral load was detected in these specimens. The causative agent was genotyped by sequencing of several genes as a variant of the European genotype E2 containing several unique single nucleotide polymorphisms. Despite all measures, there was progressive septic shock, and the patient died due to multi-organ failure. Immunocompromised adults without varicella history are at high risk to develop life-threatening complications of varicella. Antiviral therapy with acyclovir can only be successful when administered as early as possible on suspicion of varicella infection in this group of patients. The most effective method to prevent severe varicella in immunocompromised patients is active immunization prior to immunosuppressive therapy.

[Merkel cell carcinoma--clinically often misjudged]

Merkel cell carcinoma is a rare, rapidly growing, highly malignant dermal tumor which occurs preferentially on light-exposed skin in advanced age. The course of the disease is frequently characterized by the occurrence of lymph node metastases and local recurrences, even in the first year after removal of the primary tumour. The five-year overall survival rate is only about 65 %, despite rigorous therapy. The histological pattern is characterized by trabecular strands of small, uniform cells with large basophilic nuclei and typical neuroendocrine granules. The diagnosis is confirmed immunohistochemically by neuroendocrine and epithelial markers. The excision of the primary tumor is regarded as first-line therapy. Adjuvant radiatiotherapy is almost always indicated and should also include lymph node drainage. In the stage of nodal disease, a combination of excision and radiotherapy is recommended. Adjuvant chemotherapy can be applied in this stage, as in small-cell bronchial carcinoma. The prognostic advantage has, however, not been proven. Despite good response to radiatiotherapy and chemotherapy, with at least prolonged recurrence-free intervals, Merkel cell carcinoma is rarely curable at the distant metastasizing stage. Individually defined, aggressive treatment,including radiatiotherapy, may in future considerably improve the prognosis, especially in the early stages of the disease.

Photodynamische Therapie von Lidbasaliomen bei 13-jährigem Patienten mit Gorlin-Goltz-Syndrom

BACKGROUND

Gorlin Goltz syndrome is a rare, autosomal dominant inherited disease that is characterised by multiple basal cell carcinomas (BCC) including the periorbital region and eye lids. We report a severe infantile manifestation with lid involvement treated by photodynamic therapy (PDT).

PATIENT

A 13-year-old boy with Gorlin Goltz syndrome presented with multiple confluent BCC on both eye lids and the skin of neck and trunk. Multiple bilateral periorbital confluent and surgically not removable BCC were treated by topical PDT.

RESULTS

Numerous superficial BCC were successfully treated by photodynamic therapy with remarkable cosmetic results.

CONCLUSION

In cases of numerous confluent and surgically not removable BCC, PDT represents an effective therapy. Frequent monitoring is necessary to maintain the clinical outcome.

Gain of 11q/cyclin D1 overexpression is an essential early step in skin cancer development and causes abnormal tissue organization and differentiation

Non-melanoma skin cancers, in particular keratoacanthomas (KAs) and squamous cell carcinomas (SCCs), have become highly frequent tumor types especially in immune-suppressed transplant patients. Nevertheless, little is known about essential genetic changes. As a paradigm of 'early' changes, that is, changes still compatible with tumor regression, we studied KAs by comparative genomic hybridization and show that gain of chromosome 11q is not only one of the most frequent aberration (8/18), but in four tumors also the only aberration. Furthermore, 11q gain correlated with amplification of the cyclin D1 locus (10/14), as determined by fluorescence in situ hybridization, and overexpression of cyclin D1 protein (25/31), as detected by immunohistochemistry. For unraveling the functional consequence, we overexpressed cyclin D1 in HaCaT skin keratinocytes. These cells only gained little growth advantage in conventional and in organotypic co-cultures. However, although the control vector-transfected cells formed a well-stratified and orderly differentiated epidermis-like epithelium, they showed deregulation of tissue architecture with an altered localization of proliferation and impaired differentiation. The most severe phenotype was seen in a clone that additionally upregulated cdk4 and p21. These cells lacked terminal differentiation, exhibited a more autonomous growth in vitro and in vivo and even formed tumors in two injection sites with a growth pattern resembling that of human KAs. Thus, our results identify 11q13 gain/cyclin D1 overexpression as an important step in KA formation and point to a function that exceeds its known role in proliferation by disrupting tissue organization and thereby allowing abnormal growth.

[Sunlight-induced granulomatous reaction to permanent lip liner]

The demand for permanent make up and especially permanent lip liner has increased in recent years in Germany. Information about complications is not available in the medical literature, because tattooing is a trade whose results and problems are not monitored and documented, as is the case for medical procedures. A female patient with permanent lip liner experienced no complications for one year. Then, after intensive sun exposure she developed solid, linear papules along the outer margin of her lips. Histology revealed a granulomatous tissue reaction with a marked lymphohistiocytic infiltrate including epithelioid histiocytes. Treatment with topical steroids over three weeks led to a complete healing without relapse. To the best of our knowledge this is the first report on UV-light-induced granulomatous reaction to permanent lip liner.

Bizarre annular lesion emerging as tinea incognito. Bizarre anulare Erytheme als Ausdruck einer Tinea incognito

Tinea incognito has first been described in 1968. The term describes a tinea infection whose clinical morphology has been modified by the application of topical corticosteroids. The clinical manifestation can masquerade a number of other dermatoses and leads to misdiagnosis of annular eruptions. We describe a patient who showed a bizarre appearance of annular, inflammatory skin lesions at the umbilical region. Mycological culture yielded Microsporum canis.

Das Analekzem und seine benignen Simulatoren

Perianal dermatitis is one of the most common proctological disorders. Concerning the etiology, three different types of dermatitis must be distinguished-the most common irritative contact dermatitis, atopic dermatitis and allergic contact dermatitis. The correct diagnosis is essential for adequate and successful treatment. A variety of benign and malignant disorders must be considered in the differential diagnosis of anal dermatitis. Dermatitic clinical disorders which do not respond to therapy should always be biopsied.

Simulatoren des chronischen Analekzems

Several premalignant and malignant neoplasms clinically appear as chronic eczematous lesions of the perianal region and have to be distinguished from benign processes. Anal intraepithelial neoplasia (AIN) presenting as bowenoid papulosis and perianal Bowen disease is a precursor lesion for invasive squamous cell carcinoma. When AIN is widespread, persistent or progressive, an underlying immunosuppression should get excluded. Verrucous carcinoma of the perianal region is a highly differentiated variant of squamous cell carcinoma characterized as a slowly growing but locally invasive tumor. Extramammary Paget disease (EMP) is an intraepithelial adenocarcinoma of the skin with apocrine differentiation. Along with EMP, basal cell carcinoma, Langerhans cell histiocytosis and cutaneous T-cell lymphoma should be included in the differential diagnosis for lesions simulating chronic perianal dermatitis. In such situations, biopsies and histopathologic examination are imperative to avoid delayed diagnosis and assure prompt therapy.

[Facial folliculo-sebaceous cystic hamartoma. Treatment with CO2 and Er:YAG lasers]

Folliculo-sebaceous cystic hamartoma (FCH) is defined as an adnexal hamartoma. The histopathological findings of FCH are equivalent to a very late stage of trichofolliculoma. The clinical appearance of FCH is unspecific. For this reason in the majority of cases it is only the histopathological examination that leads to the diagnosis of FCH. Up to now FCH has been treated with surgical procedures. We combined the use of both CO2 and Er:YAG lasers to treat a facial FCH.

[Merkel cell carcinoma. Clinical and histological differential diagnosis, diagnostic approach and therapy]

Merkel cell carcinomas are rare tumors of the skin with an aggressive behavior and frequent regional and distant metastases. Typically, the primary is a fast-growing, painless, reddish nodule with an iceberg-like effect, broadening in the depth. On the trunk and the buttocks, deep clinically rather inconspicuous nodules can occur. The clinical differential diagnosis of the Merkel cell carcinoma includes skin metastases, malignant lymphomas, malignant adnexal tumors and cysts when the tumor is located deep in the soft tissue (e.g. on the buttocks). Histological and immunohistochemical analysis is necessary for the diagnosis. The demonstration of cytokeratin 20 in the typical globular distribution pattern is of main importance in the diagnosis of Merkel cell carcinoma. Because they are very rare, Merkel cell carcinomas are infrequently diagnosed clinically, in spite of the rather characteristic picture. Diagnostic excision with a safety margin of 3 cm is recommended followed by an adjuvant radiotherapy. The radiation field should include the area of the draining vessels and the first regional lymph nodes. There are some reports concerning the advantage of sentinel lymph node biopsy. In distant metastases, the therapy is multimodal and palliative including surgery, radiation and chemotherapy. Because of the high incidence of regional and distant metastases, regular follow-up is important.

Actinic superficial folliculitis

Actinic superficial folliculitis was first described in 1985, and since then only three reports have been published. Clinically and histopathologically this disease is very particular and has been suggested to be considered as an entity. We report on a 30-year-old man who presented with an extensive superficial follicular pustulosis on his back, shoulders and upper chest after exposure to intense heat and subsequent sweating on a sunny day. The pustules arose within 24-36 h afterwards. Histology and immunohistochemistry revealed subcorneal pustules, suppurative folliculitis and an infiltrate consisting of T cells, macrophages and neutrophils around the hair follicle, sebaceous glands and small vessels. To the best of our knowledge this is the fourth report on actinic superficial folliculitis and the first on which a characterization of the inflammatory infiltrate has been performed. Because of the impressive, unique symptoms and the characteristic histology we agree with those who have suggested that actinic superficial folliculitis is a new entity.

[Possibilities and limits of early photography in dermatology. The "Clinique photographique de l'hôpital Saint-Louis" von 1868]

Photographic images are an intrinsic part of modern dermatology, essential for documentation, publication and teaching. Although there were no strong technical obstacles to prevent the use of black and white photographs in the atlases of the late 19th century, famous works such as Kaposi's "Handatlas der Hautkrankheiten" still utilized hand-colored copper etchings for illustration. Nevertheless, M.A. Hardy and M.A. de Montméja made an effort to introduce photography into dermatology as early as 1868. In their "Clinique photographique de l'hôpital Saint-Louis" of 1868 we find a variety of dermatological diseases, discussed and illustrated with 50 black and white photographs. The majority of these pictures were then modified with hand coloring in various shades of intensity. The authors insisted on this technique to assure the diagnostic value of the pictures. Besides an extensive review of the Atlas, we discuss the limits and perspectives of early photographic images in the "Clinique photographique" compared to the detailed hand-colored copper etchings of that time, as well as to modern color photographs.

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.

[Benign cellular fibrous histiocytoma with erosion of the phalanx]

Fibrohistiocytic tumors are characterized by the presence of fibroblast like spindle cells and histiocytes. The benign fibrous histiocytoma (dermatofibroma, BFH) as well as the malignant dermatofibrosarcoma protuberans (DFSP) and the malignant fibrous histiocytoma (MFH) belong to this group. A recurrent painful, hard 2 cm tumor on the left hallux of a 54-year-old woman led to an erosion of the underlying phalanx. The patient had suffered from ingrown toenails for more than 10 years. Histologically there was a deep penetrating fibrohistiocytic tumor that grew in a storiform pattern with interspersed foam cells. The tumor was CD34 negative and mitoses were scarce. The diagnosis was benign cellular fibrous histiocytoma (BZFH). BZFH belong to the group of BFH with a high recurrence rate especially after incomplete removal. Damage to the underlying bone has not been reported so far.

[Severe allergic contact dermatitis with generalized spread due to bufexamac presenting as the "baboon" syndrome]

HISTORY AND CLINICAL FINDINGS

A 48-year-old woman presented with acute, pruritic, sharply demarcated, erythematous, maculopapulous exanthem in the anogenital area with disseminated maculae over the back. Several days before, the patient had applied as topical treatment a bufexamac-containing ointment to the anal region.

INVESTIGATIONS

The patch test showed an allergic test reaction to bufexamac.

DIAGNOSIS

The case presents a serious allergic contact dermatitis with generalization, imitating a baboon syndrome, unequivocally linked to the previous topical treatment.

CONCLUSION

During the last 10 years allergic reactions to bufexamac have increasingly been reported, sometimes with erythema multiforme-like reactions. Because of the high rate of sensitization, the serious clinical course of bufexamac allergy and the insidious symptoms of this side effect, sometimes mimicking the disease to be treated, the substance should be used neither for proctological nor for dermatological diseases, even more as these patients are considered to be at high risk of developing allergic contact dermatitis because of the abnormal skin barrier. Considering the data presented, the use of bufexamac should be critically reassessed.

[Heinrich Köbner and the "isomorphic phenomenon". History and review of the literature]

The isomorphic phenomenon belongs to the probably most well-known entities of dermatology and is closely connected to the man who was the first to describe it. Today the Koebner phenomenon is well documented in a number of skin diseases and still of considerable interest. Heinrich Koebner first reported his observation in 1872 and caused considerable diverse discussion about the origin of psoriasis in the following years. Heinrich Koebner is not only well known as "father" of the Koebner phenomenon, but also as a founder of the university dermatology clinic and pioneer of dermatology in Breslau. We not only describe the life of Heinrich Koebner, but also discuss the evolution of the term "Koebner phenomenon" and its current status.

[First descriptions in the "International atlas of rare skin diseases" of 1886]

In the history of dermatology, we find an outstanding example of scientific collaboration of leading dermatologists leading to an international publication in the late 19th century. Published by Malcolm Morris, Paul Gerson Unna, Henry-Camille Chrysostome Leloir and Louis Adolphus Duhring, the "International Atlas of Rare Skin Diseases" focused on rare and unique cases in dermatology. This concept, extraordinary for the time of publication, was found to be very successful. Numerous first descriptions are found in the "International Atlas", such as porokeratosis of Mibelli, acanthosis nigricans of Pollitzer and Janovsky and also psorospermosis of Darier. The focus on distinct and detailed descriptions to promote progress in the science of dermatology sets this effort apart from all previous atlases. Therefore, the "International Atlas was one of the first steps leading to the modern concepts of scientific publication in dermatology.

PTEN/MMAC1 expression in melanoma resection specimens

PTEN/MMAC1, a tumour suppressor gene located on chromosome 10q23.3, has been found to be deleted in several types of human malignancies. As the chromosomal region 10q22-qter commonly is affected by losses in melanomas, we addressed this gene as tumour suppressor candidate in melanomas. Investigating PTEN/MMAC1 expression at mRNA level by semi-quantitative reverse transcription-polymerase chain reaction, we did not find a statistically significant down-regulation in melanoma resection specimens in comparison to acquired melanocytic nevi from which melanomas quite often are known to arise. Upon immunohistochemistry, PTEN/MMAC1 protein expression in melanomas was not lost. Sequencing the PTEN/MMAC1 cDNAs in 26 melanoma resection specimens (21 primary melanomas, five metastases), we detected three point mutations and two nucleotide deletions which did not represent genetic polymorphisms. With respect to the predicted protein sequences, all three point mutations were silent whereas the two frame shifts at the extreme C-terminus resulted in a loss of the putative PDZ-targeting consensus sequence. As loss of this motif possibly impairs localization and function of PTEN/MMAC1 in the two corresponding primary tumours, alterations of this tumour suppressor protein may participate in some melanomas.