Histopathology of Spitz naevi and "Spitzoid" melanomas

Noninvasive imaging exploration of phacomatosis pigmentokeratotica using high-frequency ultrasound and optical coherence tomography: Can biopsy of PPK patients be avoided?

BACKGROUND

Phacomatosis pigmentokeratotica (PPK) is a distinct and rare type of epidermal nevus syndrome characterized by coexisting nonepidermolytic organoid sebaceous nevus (SN) with one or more speckled lentiginous nevi (SLN). Atypical nevi including compound Spitz and compound dysplastic may manifest within regions of SLN. Patients with PPK, or similar atypical nevus syndromes, may be subject to a significant lifetime number of biopsies, leading to pain, scarring, anxiety, financial burden, and decreased quality of life. The current literature includes case reports, genetics, and associated extracutaneous symptoms of PPK, but use of noninvasive imaging techniques have not been explored. We aim to investigate the value of high-frequency ultrasound (HFUS) and optical coherence tomography (OCT) in discriminating morphological features of pigmented lesions and nevus sebaceous within one patient with PPK.

MATERIALS AND METHODS

Two modalities, (1) HFUS imaging, based on acoustic properties and (2) OCT imaging, based on optical properties, were used to image a patient with PPK. Benign pigmented lesions, which may raise clinical suspicion for significant atypia, and nevus sebaceous, were selected on different areas of the body to be studied.

RESULTS

Five pigmented lesions and one area of nevus sebaceous were imaged and analyzed for noninvasive features. Distinct patterns of hypoechoic features were seen on HFUS and OCT.

CONCLUSION

HFUS provides a deep view of the tissue, with ability to differentiate gross structures beneath the skin. OCT provides a smaller penetration depth and a higher resolution. We have described noninvasive features of atypical nevi and nevus sebaceous on HFUS and OCT, which indicate benign etiology.

Modulation of Intersectin-1s Lung Expression Induces Obliterative Remodeling and Severe Plexiform Arteriopathy in the Murine Pulmonary Vascular Bed

Murine models of pulmonary arterial hypertension (PAH) that recapitulate the plexiform and obliterative arteriopathy seen in PAH patients and help in defining the molecular mechanisms involved are missing. Herein, we investigated whether intersectin-1s (ITSN) deficiency and prolonged lung expression of an ITSN fragment with endothelial cell (EC) proliferative potential (EH_ITSN), present in the lungs of PAH animal models and human patients, induce formation of plexiform/obliterative lesions and defined the molecular mechanisms involved. ITSN-deficient mice (knockout/heterozygous and knockdown) were subjected to targeted lung delivery of EH_ITSN via liposomes for 20 days. Immunohistochemistry and histological and morphometric analyses revealed a twofold increase in proliferative ECs and a 1.35-fold increase in proliferative α-smooth muscle actin-positive cells in the lungs of ITSN-deficient mice, transduced with the EH_ITSN relative to wild-type littermates. Treated mice developed severe medial wall hypertrophy, intima proliferation, and various forms of obliterative and plexiform-like lesions in pulmonary arteries, similar to PAH patients. Hemodynamic measurements indicated modest increases in the right ventricular systolic pressure and right ventricle hypertrophy. Transcriptional and protein assays of lung tissue indicated p38^MAPK-dependent activation of Elk-1 transcription factor and increased expression of c-Fos gene. This unique murine model of PAH-like plexiform/obliterative arteriopathy induced via a two-hit pathophysiological mechanism without hypoxia provides novel druggable targets to ameliorate and, perhaps, reverse the EC plexiform phenotype in severe human PAH.

Melanoma in pediatric, adolescent, and young adult patients

The family practitioner, pediatrician, and dermatologist all have potential roles in the primary prevention, diagnosis, and treatment of localized thin melanomas. Surgical and medical oncologists are often involved when controversy arises over the nature of the skin lesion or whether sentinel lymph node (SLN) biopsies and adjuvant therapy are to be contemplated. This overview of melanoma will deal with the primary and nodal pathology, surgery, and medical therapy of melanoma in pediatric, adolescent, and young adult patients--and will raise areas of controversy that are only recently being addressed in databases of cases from this age group.

Melanocytic aggregation in the skin: diagnostic clues from lentigines to melanoma

Pigmented skin lesions are among the most common skin lesions. Among them, melanocytic proliferations are morphologically diverse and their behavior may be difficult to discern with certainty. Researchers must be able to distinguish melanocytic from nonmelanocytic pigmented skin lesions and, in particular, benign from malignant lesions. The majority of these lesions can be diagnosed with ease; however, a minority of cases is difficult and have potential for error. The authors have systematically analyzed the clinical and dermoscopic features of melanocytic skin lesions, so as to increase in vivo diagnostic accuracy.

BRAF and NRAS mutations in spitzoid melanocytic lesions

BRAF mutations are common events in a variety of melanocytic nevi and primary cutaneous melanomas. We have previously found BRAF mutations in 82% of nevi, consisting of congenital, common acquired and dysplastic types, and 33% of primary cutaneous melanomas other than the spitzoid type, similar to other published reports. A small number of studies have evaluated Spitz nevi and have failed to detect any lesions possessing a BRAF mutation. Only one study included categories of atypical Spitz nevus and borderline lesions suspected to be spitzoid melanomas, along with classic Spitz nevi and spitzoid melanomas. We examined a spectrum of spitzoid lesions that included 48 Spitz nevi, some with atypical features, seven atypical (borderline) Spitz tumors, and 13 spitzoid melanomas. BRAF mutations were detected in 12 of 68 spitzoid lesions, of which two were spitzoid melanomas and 10 were Spitz nevi. Five of the 10 Spitz nevi with BRAF mutations were altered by more than usual cytologic atypia and/or architectural atypia overlapping with dysplastic nevi, or irritation/inflammation; one desmoplastic Spitz nevus had a BRAF mutation. These results indicate that a small subset of Spitz nevi, some with atypical histologic features, possess BRAF mutations. Therefore, the BRAF mutational status does not separate all Spitz nevi from spitzoid melanomas and non-Spitz types of melanocytic proliferations, contrary to previous reports.

Malignant melanoma in childhood and adolescence: Report of 13 cases

We reviewed all cases of malignant melanoma in children younger than 17 years of age who were evaluated at Sainte Justine Hospital, a tertiary care pediatric center, between 1980 and 2002. The medical records and histologic features of all cases were reviewed. Thirteen cases were identified, 4 boys and 9 girls. Fifty-three percent of patients were prepubescent. None of the patients had a predisposing condition (eg, giant congenital nevi, dysplastic nevus syndrome, or xeroderma pigmentosum). One patient had had chemoradiotherapy previously for an undifferentiated pleuropulmonary malignant tumor (blastoma) and another patient had Down syndrome. The most frequent reason for initial consultation was a recent increase in size of the lesion. Three patients had pyogenic granuloma-like lesions. Eighty-five percent of the observed melanomas were nodular in type. Tumor thickness ranged from 0 to 6 mm with a median and mean thickness of 2.8 and 3.2 mm, respectively. The overall 5-year survival rate was 58.8%. Lack of awareness and delay in diagnosis may lead to a higher incidence of thick and intermediate melanoma in children. Because it appears that the majority of melanomas in childhood and adolescence occur de novo, clinicians should consider this condition in the differential diagnosis of any suspect lesion in children and adolescents even without an identified predisposing factor.

Pathology of melanocytic lesions: New, controversial, and clinically important issues

Patients with primary cutaneous melanocytic lesions rely not only on the knowledge, skills, and experience of their treating clinician but also on the fundamentally important input of their pathologist for accurate diagnosis and appropriate management. Free and precise communication between pathologists and surgeons is important and undoubtedly improves patient care, particularly when managing difficult or complicated cases. To provide both patient and surgeon with the necessary information they require to make the most appropriate decisions, the pathology report should include all pathologic factors that are important in determining the patient's prognosis and management. Use of a synoptic format for pathology reporting of melanomas can facilitate this. Recent studies have established that the dermal mitotic rate of a primary cutaneous melanoma is a major prognostic determinant, and have shown that its assessment and that of other important histopathologic prognostic variables are reproducible between pathologists. Sentinel node (SN) biopsy has provided a minimally invasive procedure that can accurately predict the regional node status of melanoma patients. It is well demonstrated that the use of immunohistochemical stains assists in the detection of melanoma micrometastases in SNs, although it remains unclear which is the optimal pathologic protocol for SN evaluation and whether there is a role for reverse transcriptase polymerase chain reaction (RT-PCR) in SN assessment. False negative SN biopsies may occur as a result of errors in lymphatic mapping or sentinel lymphadenectomy, or because of a deficiency in the process of histopathologic evaluation. Recent studies have shown that the likelihood of non-SN involvement when the SN is positive correlates mostly with the extent of SN involvement, in particular the tumor penetrative depth (defined as the maximum distance of melanoma cells from the inner margin of the SN capsule). It appears that assessment of the micromorphometric features of positive SNs may be useful in predicting which patients have a low probability of having metastatic tumor in non-SNs, and therefore in selecting patients who potentially may be spared a completion lymph node dissection. It is likely that future advances in our understanding of the molecular biology of melanoma will provide new insights into tumor classification, improve diagnostic accuracy and prognostic ability, and lead to the development of more precisely targeted therapies.

Sentinel lymph node biopsy for patients with problematic spitzoid melanocytic lesions: a report on 18 patients

BACKGROUND

Spindle and/or epithelioid melanocytic proliferations that display overlapping histopathologic features of Spitz nevus and Spitz-like melanoma are diagnostically difficult and controversial melanocytic tumors. There are reports of such lesions metastasizing to regional lymph nodes, with a few widely disseminating, resulting in death.

METHODS

The authors reviewed clinical and histopathologic data on all patients with atypical or borderline spitzoid melanocytic proliferations who underwent sentinel lymph node biopsy (SLNB). They examined how frequently histologically problematic or borderline spitzoid melanocytic lesions metastasized to sentinel lymph nodes (SLNs) and which clinical or histologic features, if any, predisposed patients to a higher risk lesion.

RESULTS

Six male patients and 12 female patients, ages 5-32 years (mean, 16 years), had tumors ranging in size from 1.2 mm to 7.9 mm (mean, 3.5 mm) in thickness. Atypical histologic features that were present most frequently included incomplete maturation (18 of 18 patients), deep dermal mitoses (16 of 18 patients), nuclear pleomorphism (10 of 18 patients), and focal sheet-like growth (10 of 18 patients). Eight of 18 patients (44%) had SLN metastasis and were offered adjuvant treatment. One of eight patients with SLN positive results who underwent regional lymphadenectomy had one additional involved lymph node. All 18 patients were alive and well with no evidence of recurrent or metastatic disease after a follow-up of 3-42 months (mean, 12 months).

CONCLUSIONS

Histologically atypical or borderline spitzoid, melanocytic tumors are diagnostically challenging and controversial melanocytic lesions, some of which represent unrecognized melanomas. SLNB aids in confirming a diagnosis of melanoma and identifies patients who may benefit from early therapeutic lymph node dissection and/or adjuvant therapy.