Melanoma incidence and the lifetime risk are increasing at an alarming rate in the United States and worldwide. In order to improve survival rates, the goal is to detect melanoma at an early stage of the disease. Accurate, sensitive and reliable quantitative diagnostic tools can reduce the number of unnecessary biopsies, the associated morbidity as well as the costs of care in addition to improving survival rates. The recently introduced quantitative dynamic infrared imaging system QUAINT measures differences in the infrared emission between healthy tissue and the lesion during the thermal recovery process after the removal of a cooling stress. Results from a clinical study suggest that the temperature of cancerous lesions is higher during the first 45-60 seconds of thermal recovery than the temperature of benign pigmented lesions. This small temperature difference can be measured by modern infrared cameras and serve as an indicator for melanoma in modern quantitative melanoma detectors.

The rising incidence of melanoma in children has brought increased attention to the clinical and pathologic diagnosis of pigmented lesions in the pediatric age group. Although melanoma in infancy and early childhood is often associated with large congenital nevi, in older children and teenagers it is most often sporadic, occurring in patients with a low skin phototype and substantial sun exposure. The rarity of this potentially fatal disorder demands astute clinical attention and a high index of suspicion for atypical lesions in pediatric patients. The challenges include the difficult decision of whether to biopsy and an often equivocal pathologic diagnosis. These diagnostically challenging and equivocal lesions lead to a degree of uncertainty regarding additional workup, prognosis, potential therapy, and follow-up plans. Consultation with a specialty dermatopathologist can be very helpful, and advanced molecular diagnostic techniques may be used in selected circumstances. Although still controversial, good evidence exists to justify a role for sentinel lymph node biopsy. Patients with atypical melanocytic proliferations have a high rate of positive sentinel lymph nodes; however, their outcomes are clearly better than in similarly staged adults with conventional melanoma. With the multiple variables involved and the relative lack of prospectively derived evidence, clinical decision-making is challenging and patients and families may experience considerable stress. This article provides data and weighs the pros and cons of a rationale for decision-making in pediatric and young adult patients with diagnostically challenging melanocytic lesions.

Purpose:

  To investigate the presence of KIT gene mutations and immunoreactivity in 85 conjunctival melanocytic tumours and to clarify the role of KIT as a potential therapeutic target in this group of patients.

Methods:

  Eighty-five conjunctival pigmented tumours [27 melanomas, 12 primary acquired melanosis (PAMs) and 46 nevi] were immunostained for KIT. Intensity and pattern of expression were evaluated. Molecular analysis to identify KIT mutations was performed in 15 selected cases (tumour-rich areas >50%). KIT immunostaining score and pattern were statistically related to patients' age, sex, diagnostic category, presence of relapse, disease-free survival, presence of metastases, metastasis-free survival, limbal versus nonlimbal tumour location and thickness of melanomas.

Results:

  KIT stains were documented in 48% of melanomas, 50% of PAMs and 24% of nevi. The mean score of KIT staining in the melanomas/PAMs group was significantly different from nevi (p = 0.0076). No statistically significant differences were detected between either c-kit immunostaining score or pattern and each of the other clinico-pathologic parameters considered. No KIT gene mutations were detected in melanomas and nevi. A silent mutation/polymorphism in KIT exon 13 was found in one PAM.

Conclusions:

  Despite the high level of KIT immunostains in PAMs and melanomas, this parameter seems not to be a good predictor of the presence of molecular mutations. KIT-activating mutations should be considered an uncommon event in this tumour.

The incidence of cutaneous melanoma is increasing worldwide. Since it is an aggressive neoplasm, it is difficult to treat in advanced stages; early diagnosis is important to heal the patient. Melanocytic nevi are benign pigmented skin lesions while atypical nevi are associated with the risk of developing melanoma because they have a different histological pattern than common nevi. Thus, the clinical diagnosis of pigmented lesions is of great importance to differentiate benign, atypical and malignant lesions. Dermoscopy appeared as an auxiliary test in vivo, playing an important role in the diagnosis of pigmented lesions, because it allows the visualization of structures located below the stratum corneum. It shows a new morphological dimension of these lesions to the dermatologist and allows greater diagnostic accuracy. However, histopathology is considered the gold standard for the diagnosis.To establish the sensitivity and specificity of dermoscopy in the diagnosis of pigmented lesions suspected of malignancy (atypical nevi), comparing both the dermatoscopic with the histopathological diagnosis, at the Dermatology Service of the outpatient clinic of Hospital de Base, São José do Rio Preto, SP.Analysis of melanocytic nevi by dermoscopy and subsequent biopsy on suspicion of atypia or if the patient so desires, for subsequent histopathological diagnosis.Sensitivity: 93%. Specificity: 42%.Dermoscopy is a highly sensitive method for the diagnosis of atypical melanocytic nevi. Despite the low specificity with many false positive diagnoses, the method is effective for scanning lesions with suspected features of malignancy.

BACKGROUND:

Seborrhoeic keratoses (SKs) are common benign epidermal neoplasms in humans and are rarely diagnosed in the dog. These circumscribed, raised, variably pigmented plaques arise in middle aged to older humans, with a focal or multicentric distribution; although common, the underlying cause of these lesions is not known. Although less common in the dog, the lesions are similar and have features that overlap with papillomavirus-associated pigmented viral plaques. HYPOTHESIS/

OBJECTIVES:

Seborrhoeic keratoses in the dog are negative for canine papillomavirus.

ANIMALS:

Eleven cases of SK from a 12 year period were reviewed.

METHODS:

This was a retrospective study of the histopathological findings and case histories. Complete clinical records following collection of the skin biopsy were available in five of 11 cases. Immunohistochemistry was performed for all cases; PCR analysis was carried out for papillomavirus in six cases.

RESULTS:

Histologically, SKs had an exophytic to mildly endophytic epidermal proliferation, creating a papillomatous to acanthotic, hyperkeratotic, frequently pigmented plaque. There was an absence of hypergranulosis or viral cytopathic effect; PCRs for canine papillomavirus within the formalin-fixed paraffin-embedded skin biopsies were negative. No breed, sex or site predilection was recognized. The mean age at biopsy of the lesions was 8.8 years (range 5-14 years).

CONCLUSIONS

AND CLINICAL IMPORTANCE: Histopathological features and negative papillomavirus status distinguish SK as an important differential diagnosis for pigmented viral plaques in dogs.

Pigmented villonodular synovitis (PVNS) arising from the elbow joint is extremely rare; only 24 cases have been reported. It is extremely difficult to differentiate PVNS from other soft tissue tumors on the basis of imaging findings alone. Therefore, a biopsy is required for definitive diagnosis. A 20-year-old female reported a mass on her right elbow. Physical examination revealed a tumor measuring 3.0x3.0 cm. Magnetic resonance imaging (MRI) revealed that the signal intensity of the tumor was isointense to muscle on T1-weighted images; however, it was hyper- or isointense to muscle on T2-weighted images. In images obtained by gadolinium-enhanced MRI, the margin of the tumor was well-contrasted. Thallium (Tl)-201 scintigrams revealed an abnormal accumulation in the area of the mass in the early and delayed phases. On the basis of clinical findings, imaging characteristics and incision biopsy results, localized PVNS was diagnosed and marginal excision was performed. We thus identified an extremely rare case of PVNS arising from the elbow joint. When interpreting Tl-201 images for the assessment of bone and soft tissue lesions, it is important to recognize PVNS as a condition that simulates malignant tumors. Furthermore, PVNS should be considered in the differential diagnosis when increased Tl-201 activity is closely related to the joint. MRI aids in the differentiation by demonstrating features of hemosiderin degradation products. These findings are likely to be extremely helpful in the differential diagnosis of bone and soft tissue tumors.

Melanoma diagnosis in dogs can be challenging due to the variety of histological appearances of canine melanocytic neoplasms. Markers of malignancy are needed. Receptor for activated C-kinase 1 (RACK1) was found to characterize melanomas in other mammals. We investigated the value of RACK1 detection in the classification of 19 cutaneous and 5 mucosal melanocytic neoplasms in dogs. These tumors were categorized as melanocytomas or benign and melanomas or malignant after evaluation of their morphology, mitotic index, and Ki-67 growth fraction. Using immunofluorescence, we confirmed microphthalmia-associated transcription factor (MITF) as a marker of normal and transformed melanocytic cells in dog tissues. All control (n = 10) and tumoral (n = 24) samples stained positively for MITF (34/34, 100%). Whereas RACK1 was not detected in healthy skin melanocytes, melanocytic lesions were all positive for RACK1 signal (24/24, 100%). RACK1 cytoplasmic staining appeared with 2 distinct distribution patterns: strong, diffuse, and homogeneous or granular and heterogeneous. All melanoma samples (13/13, 100%) stained homogeneously for RACK1. All melanocytomas (11/11, 100%) stained heterogeneously for RACK1. Immunohistochemistry was less consistent than immunofluorescence for all labelings in melanocytic lesions, which were often very pigmented. Thus, the fluorescent RACK1-MITF labeling pattern helped to distinguish melanomas from melanocytomas. Furthermore, RACK1 labeling correlated with 2 of 11 morphological features linked to malignancy: cell and nuclear size. These results suggest that RACK1 may be used as a marker in dog melanomas.

Dermal melanocytoses include a variety of congenital and acquired melanocytic lesions characterised by the presence of multiple spindle-shaped dendritic melanocytes in the dermis. These lesions are commonly found in the skin of Asians, but they can also appear in Caucasians. The Mongolian spot, nevi of Ota and Ito are the most common morphological forms. We report a case of a 24-year-old Caucasian woman presented with a 10-months history of progressive darkening of the right side of her upper back. Cutaneous examination revealed a macular blue-grey hyperpigmentation of the right side of her upper back. Biopsy specimen from the macule showed multiple darkly pigmented, spindle-shaped dendritic melanocytes in the superficial dermis, interstitially arranged between collagen bundles. The diagnosis of nevus of Ito was established. Our patient is maintaining vigilance in dermatology consultation.

Dermatofibromas are benign skin lesions that consist of pigmented papules or nodules. They produce the dimple sign when laterally squeezed and are usually found on the legs. These clinical features lead to the diagnosis in most cases. However, the differential diagnosis with other lesions, such as atypical nevi and melanoma can be difficult, and the dermoscopy may help the diagnosis. There are several dermoscopic patterns associated with dermatofibromas, the most common being a central white scar like patch with delicate pigment network at the periphery. This article describes the case of a patient who had eleven clinically similar dermatofibromas, with four distinct patterns when submitted to dermoscopic examination.

Purpose:

  To examine spectral domain optical coherence tomographic (OCT) and histological images from comparable retinal photocoagulation lesions in rabbits, and to correlate these images with comparable OCT images from patients.

Methods:

  508 rabbit lesions were examined by HE-stained paraffin histology. 1019 rabbit lesions versus 236 patient lesions were examined by OCT, all at the time-points 1 hr, 1 week and 4 weeks after photocoagulation. We analysed 100 μm lesions (in humans) and 133 μm lesions (in rabbits) of 200 ms exposures at powers titrated from the histological threshold up to intense damage. Lesions were matched according to morphological criteria.

Results:

  Dome-shaped layer alterations, retinal infiltration by round, pigmented cells, outer nuclear layer interruption, and eventually full thickness retinal coagulation are detectable in histology and OCT. Horizontal damage extensions are found 1½ times larger in OCT. More intense irradiation was necessary to induce comparable layer affection in rabbit OCT as in histology. Restoration of the inner retinal layers is only shown in the OCT images. Comparable primary lesions caused more pronounced OCT changes in patients than in rabbits during healing.

Conclusions:

  Optical coherence tomographic images indicate different tissue changes than histologic images. After photocoagulation, they show wider horizontal damage diameters, but underestimate axial damage particularly during healing. Conclusions on retinal restoration should not be drawn from OCT findings alone. Retinal recovery after comparable initial lesions appears to be more complete in rabbit than in patient OCTs.