Immunohistochemistry in the diagnosis of cutaneous neoplasms

In recent years, there has been a significant increase in the number of diagnostic immunohistochemical stains available to pathologists and dermatopathologists. Immunohistochemistry has become an indispensable tool in dermatopathology, not only in diagnosis but also in the treatment and prognostication of cutaneous neoplasms. In this review we attempt to outline current, as well as new, immunohistochemical stains of relevance in the diagnosis and classification of cutaneous neoplasms.

Pediatric melanoma: a single-institution experience of 150 patients

PURPOSE

Differentiating pigmented skin lesions from malignant melanoma in the pediatric population has been a challenge. Despite guidelines describing clinical features and histopathologic criteria to distinguish these lesions, misdiagnoses still occur. We report our experience over 30 years in a pediatric population with malignant melanoma.

METHODS

We performed a retrospective review of 150 pediatric patients treated for malignant melanoma between 1973 and 2007 at our institution. Outcomes measured included age, Breslow thickness, Clark level of invasion, tumor location, local and distant failure rates, and overall survival.

RESULTS

One hundred fifty pediatric patients were evaluated. The mean age was 15.1 years. The mean Breslow thickness was 2.05 mm and corresponding Clark level of invasion was 3.47. There were 43 known recurrences (29%); 29 distant, 14 nodal, and 7 local. Overall survival was 84% with a mean follow-up of 8.5 years. Sixteen patients (10.7%) were incorrectly diagnosed on initial pathologic examination. Overall survival in the misdiagnosed group was 66%.

CONCLUSION

Pigmented skin lesions in the pediatric population represent a diagnostic challenge to pathologists and clinicians. Improvements in diagnostic techniques with rigorous characterization, as well as increased physician awareness, should lead to a reduction in errors of diagnosis.

Targeting N-cadherin enhances antitumor activity of cytotoxic therapies in melanoma treatment

Malignant transformation in melanoma is characterized by a phenotype "switch" from E- to N-cadherin, which is associated with increased motility and invasiveness of the tumor and altered signaling, leading to decreased apoptosis. We hypothesized that the novel pentapeptide (ADH-1), which disrupts N-cadherin adhesion, could sensitize melanoma tumors to the cytotoxic effects of chemotherapy. N-cadherin-expressing human melanoma-derived cell lines were used to generate xenografts in animal models to study isolated limb infusion with melphalan and systemic chemotherapy with temozolomide. We report here that melphalan in combination with ADH-1 significantly reduced tumor growth up to 30-fold over melphalan alone. ADH-1 enhancement of response to melphalan was associated with increased formation of DNA adducts, increased apoptosis, and intracellular signaling changes associated with focal adhesions and fibroblast growth factor receptors. Targeted therapy using an N-cadherin antagonist can dramatically augment the antitumor effects of chemotherapy and is a novel approach to optimizing treatment for melanoma.

Defining regional infusion treatment strategies for extremity melanoma: comparative analysis of melphalan and temozolomide as regional chemotherapeutic agents

Five different human melanoma xenografts were used in a xenograft model of extremity melanoma to evaluate the variability of tumor response to regionally administered melphalan or temozolomide and to determine if various components of pertinent drug resistance pathways for melphalan [glutathione S-transferase (GST)/glutathione] and temozolomide [O(6)-alkylguanine DNA alkyltranferase (AGT)/mismatch repair (MMR)] could be predictive of tumor response. Xenograft-bearing rats underwent regional isolated limb infusion with either melphalan (90 mg/kg) or temozolomide (2,000 mg/kg). The levels of AGT activity, GST activity, glutathione level, and GST/AGT expression were examined in this group of xenografts and found to be quite heterogeneous. No correlation was identified between melphalan sensitivity and the GST/glutathione cellular detoxification pathway. In contrast, a strong correlation between the levels of AGT activity and percentage increase in tumor volume on day 30 (r = 0.88) was noted for tumors treated with temozolomide. Regional therapy with temozolomide was more effective when compared with melphalan for the xenograft with the lowest AGT activity, whereas melphalan was more effective than temozolomide in another xenograft that had the highest AGT activity. In three other xenografts, there was no significant difference in response between the two chemotherapy agents. This study shows that AGT activity may be useful in predicting the utility of temozolomide-based regional therapy for advanced extremity melanoma tumors. Our observations also point out the limited ability of analysis of the GST/glutathione pathway to predict response to chemotherapies like melphalan whose resistance is primarily mediated through a complex mechanism of detoxification.

Self-healing juvenile cutaneous mucinosis: Cases highlighting subcutaneous/fascial involvement

BACKGROUND

Self-healing juvenile cutaneous mucinosis is a rare disease affecting young people characterized by transient cutaneous lesions and sometimes mild inflammatory symptoms. The deep dermal and subcutaneous features of this disorder have not yet been well described.

OBJECTIVE

The purpose of our study was to present 3 cases of self-healing juvenile cutaneous mucinosis in which the histopathologic features caused diagnostic confusion between this disorder and proliferative fasciitis.

METHODS

The study includes clinical and histologic findings of 3 patients, complemented by a literature review.

RESULTS

The histologic descriptions of nodular lesions in self-healing juvenile cutaneous mucinosis reveal features of proliferative fasciitis, including a myxoid stroma and gangliocyte-like giant cells.

LIMITATIONS

Self-healing juvenile cutaneous mucinosis is a rare condition and has not been frequently reported in medical literature. Our findings are based on the pathologic features of 3 patients.

CONCLUSIONS

Our findings further elucidate the histologic features of self-healing juvenile cutaneous mucinosis and expand the differential diagnosis for entities in which gangliocyte-like giant cells are noted.

Differential expression of N-cadherin distinguishes a subset of metastasizing desmoplastic melanomas

Desmoplastic melanoma is a variant of spindle cell melanoma considered at low risk for distant metastases when compared with other forms of melanoma. The emphasis in the differential diagnosis of desmoplastic melanomas has been placed mostly in distinguishing it from scars and other benign spindle cell proliferations. In contrast, recognizing a subset of desmoplastic melanomas with higher metastatic potential has proven more difficult. We studied the expression of N-cadherin in 21 desmoplastic melanomas. The expression of N-cadherin was examined by immunohistochemistry using archive material and a mouse anti-N-cadherin monoclonal antibody previously shown to react in routinely processed paraffin-embedded tissues. Of 21 cases, N-cadherin was strongly positive in 10, only weakly or focally positive in 3, and negative in 8. Seven of 21 patients had distant metastases, and N-cadherin was strongly positive in 6 of those 7 cases. In contrast, only 1 of 11 patients within the group of N-cadherin-negative or weakly positive tumors had distant metastases. Our results show that strong N-cadherin expression in desmoplastic melanoma correlates with distant metastases and potentially more aggressive behavior. In contrast, desmoplastic melanomas with low metastatic potential are mostly negative or only focally positive for N-cadherin. The data suggest that N-cadherin may be a useful marker in recognizing a subset of desmoplastic melanoma with higher metastatic potential.

Basal cell-signet-ring squamous cell carcinoma of the eyelid

A 93-year-old woman developed a mass on her right lower eyelid that was present for more than 6 months but underwent rapid expansion during several weeks prior to her ophthalmological evaluation. Examination revealed an approximately 1.8 cm in diameter, fleshy, fungating growth involving more than 60% of the right lower eyelid. Excisional biopsy disclosed a neoplasm arising from the epidermis composed of adjoining basal cell and signet-ring squamous cell carcinoma, without a transition zone. The cells comprising the basal and squamous cell carcinomas were distinct immunophenotypically, with only the basal cell carcinoma reacting with Ber-EP4 and CAM 5.2 antibodies. To our knowledge, this case represents the first example of a collision tumor composed of basal cell and signet-ring squamous cell carcinoma.

Histopathologic Characteristics, Recurrence Patterns, and Survival of 129 Patients With Desmoplastic Melanoma

BACKGROUND

Desmoplastic melanoma (DM) has been associated with higher local recurrence rates than other types of cutaneous melanoma. Current controversies regarding locoregional treatment strategies warrant further investigation.

METHODS

Retrospective review of a prospectively maintained melanoma database identified 129 patients with DM out of >12,500 melanoma patients referred for treatment from 1980 to 2003. Clinical and histopathologic characteristics, recurrence, and survival were analyzed.

RESULTS

The median follow-up was 4.0 years. Of the 129 patients identified, 82 (63.6%) were male, and the median age was 55.2 years. American Joint Committee on Cancer staging was I, II, and III in 25.6%, 68.0%, and 6.4% of patients, respectively, and the mean tumor thickness was 4.42 mm. Overall survival was 76% at 5 years and 64% at 10 years; median survival was 13.0 years. A total of 51 patients (39.5%) experienced disease recurrence, with a median time to recurrence of 1.3 years. The first recurrence was local in 18 patients (14.0%), nodal in 18 patients (14.0%), and distant in 15 patients (11.6%), with median survivals of 6.7, 7.8, and 1.8 years, respectively. Statistically significant predictors of recurrence were a final positive margin status and stage, and predictors of overall survival were patient age and stage.

CONCLUSIONS

Compared with other types of melanoma, DMs do demonstrate a tendency toward local recurrence, thus suggesting that narrower excision margins may not be appropriate in this population. Scrutiny of final surgical margins is critical to the local management of DM. In addition, the potential for regional nodal involvement must be considered at the time of diagnosis and during surveillance for disease recurrence.

CD10 expression in trichoepithelioma and basal cell carcinoma

BACKGROUND

Trichoepithelioma (TE) is a benign neoplasm that shares both clinical and histologic features with basal cell carcinoma (BCC). However, it is important to distinguish these neoplasms. Limited immunohistochemical stains are available to separate these two tumors.

METHODS

CD10 protein immunohistochemistry was performed on paraffin-embedded biopsies of 13 TE and 23 BCC diagnosed by routine microscopy. Cases were analyzed for pattern of CD10 expression by tumor cells and surrounding stroma.

RESULTS

Twelve of 13 (92%) TE showed positive stromal immunoreactivity. Of these, eight cases also demonstrated positivity of the papilla, and two also showed positivity of the basaloid cells. No TE demonstrated epithelial expression alone. On the other hand, expression of CD10 by basaloid cells was identified in 20 (87%) cases of BCC. Stromal positivity was also identified in three cases of BCC. Condensation of CD10-positive stromal cells around basaloid nests was statistically significant in differentiating TE from BCC (p < 0.0001). Conversely, CD10-positive basaloid cells were seen predominantly in BCC (p < 0.0001).

CONCLUSIONS

This study demonstrates a statistically significant difference in CD10 staining pattern between TE and BCC. Thus, CD10 may be a useful adjunct marker in distinguishing these tumors.

Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin

Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15%l-ascorbic acid and 1%alpha-tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. Inhibition of apoptosis was associated with reduced induction of caspase-3 and caspase-7. This antioxidant formulation efficiently reduced thymine dimer formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.

Cutaneous findings in patients with pulmonary arterial hypertension receiving long-term epoprostenol therapy

Pulmonary arterial hypertension (PAH) is a rare debilitating disease characterized by an increase in pulmonary vascular resistance and progressive right ventricular failure. PAH may be primary or associated with other conditions such as collagen vascular disease, portal hypertension, and HIV. Intravenous epoprostenol improves the survival, exercise tolerance, hemodynamics, and quality of life in patients with PAH and is believed to work through multiple pathways including vasodilation, opposition of smooth-muscle hypertrophy, and inhibition of platelet aggregation. Common dose-limiting side effects are flushing, jaw pain, arthralgias, myalgias, and headache, which are attributed to the vasodilatory effects of epoprostenol. In clinical practice, patients often develop persistent rash that is distinct from the flushing associated with epoprostenol. The specific findings both on physical examination and on dermatopathology have not, however, been well described. This report describes the cutaneous and dermatopathologic findings of 12 patients who developed persistent rash while receiving long-term prostacyclin for PAH.

Spitz nevi and atypical Spitz nevi/tumors: a histologic and immunohistochemical analysis

A subset of Spitz nevi poses substantial diagnostic difficulty, even among experts, due to its resemblance to malignant melanoma. These lesions are termed atypical Spitz nevi/tumors and there is currently a lack of objective criteria for predicting their biologic behavior. We compared the expression of Ki-67, p21, and fatty acid synthase by immunohistochemistry in 10 atypical Spitz nevi, 28 typical Spitz nevi, 19 compound melanocytic nevi and 18 invasive malignant melanomas. There was a progressive increase in fatty acid synthase cytoplasmic expression with statistically significant differences observed between Spitz nevi and atypical Spitz nevi (P=0.003) and between atypical Spitz nevi and malignant melanoma (P<0.050). Ki-67 nuclear staining was lower in both typical and atypical forms of Spitz lesions than in malignant melanoma (P<0.001). The degree of P21 nuclear expression in atypical Spitz nevi was not significantly different than in Spitz nevi, but was significantly greater than expression in conventional nevi and approached significance after multiple comparisons corrections for malignant melanoma. Thus, a high level of P21 expression makes a tumor more likely to be a typical or atypical Spitz nevus than a malignant melanoma, especially when coupled with a low Ki-67 index and weak expression of fatty acid synthase. These immunohistochemical observations support the concept that atypical Spitz nevi are distinct lesions of borderline biologic behavior residing between Spitz nevi and malignant melanoma. The study also compared a large array of histologic features of 16 cases of typical Spitz nevi in children with 12 typical Spitz nevi in adults. The adult lesions were significantly more likely to be intradermal and to display dermal fibroplasia, but were histologically similar to their pediatric counterparts in all other respects.

Are en face frozen sections accurate for diagnosing margin status in melanocytic lesions?

To assess the diagnostic accuracy of margin evaluation of melanocytic lesions using en face frozen sections compared with standard paraffin-embedded sections, we studied 2 sets of lesions in which en face frozen sections were used for analysis of surgical margins (13 from malignant melanomas [MMs] and 10 from nonmelanocytic lesions [NMLs]). Routine permanent sections were cut after routine processing. The slides were mixed and coded randomly. Fifteen dermatopathologists examined the cases separately. Margin status was categorized as positive, negative, or indeterminate. Kappa statistics were calculated per dermatopathologist and per case. One case from each group was excluded because epidermis was not available in the routine sections. Of 330 evaluations (22 cases, 15 dermatopathologists), there were 132 diagnostic discrepancies (40.0%): 66 each for MM and NML (mean per case for both diagnoses, 6). In 9 instances (6.8%), the change was from positive (frozen) to negative (permanent) and in 43 (32.6%), from negative (frozen) to positive (permanent). There was poor agreement between frozen and permanent sections (kappa range per dermatopathologist, -0.1282 to 0.6615). If permanent histology is considered the "gold standard" for histologic evaluation, en face frozen sections are not suitable for accurate surgical margin assessment of melanocytic lesions.

UV photoprotection by combination topical antioxidants vitamin C and vitamin E

BACKGROUND

Virtually all plants and animals protect themselves from the sun using vitamins C and E.

OBJECTIVE

The purpose of this study was to see if a combination of topical vitamins C and E is better for UV protection to skin than an equivalent concentration of topical vitamin C or E alone.

METHODS

We developed a stable aqueous solution of 15% L-ascorbic acid (vitamin C) and 1% alpha-tocopherol (vitamin E). We applied antioxidant or vehicle solutions to pig skin daily for 4 days. We irradiated (1-5x minimal erythema dose) control- and antioxidant-treated skin using a solar simulator with a 295-nm band-pass filter. On day 5, we measured antioxidant protection factor, erythema, sunburn cells, and thymine dimers.

RESULTS

The combination of 15% L-ascorbic acid and 1% alpha-tocopherol provided significant protection against erythema and sunburn cell formation; either L-ascorbic acid or 1% alpha-tocopherol alone also was protective but the combination was superior. Application during 4 days provided progressive protection that yielded an antioxidant protection factor of 4-fold. In addition, the combination of vitamins C and E provided protection against thymine dimer formation.

CONCLUSION

Appreciable photoprotection can be obtained from the combination of topical vitamins C and E. We suggest that these natural products may protect against skin cancer and photoaging.

Seasonal variation of the lipoidal matters and hypolipidaemic activity of the red alga Corallina officinalis L

The lipoidal matters of Corallina officinalis L. showed a seasonal nonsignificant quantitative variation. However, the fatty acids revealed a relative increase in the summer and winter, while unsaponifiable matter exhibited a slight increase in the spring. The GC/MS analysis of saponifiable and unsaponifiable matter of the algal samples collected in different seasons revealed that samples collected in the spring contained a low cholesterol content and high steroidal compounds as well as high polyunsaturated fatty acids. The alcohol extract, hexane extract and fatty acid fraction of this algal sample exhibited a significant hypolipidaemic activity. Also, two biologically active fractions of hydrocarbons were isolated by CC technique from the hexane fraction of C. officinalis L. and identified by GC/MS.

Severe erythroderma as a complication of continuous epoprostenol therapy

Epoprostenol is a vasodilator that is produced by vascular endothelial cells and is currently the "gold standard" therapy for patients with severe primary pulmonary hypertension or pulmonary hypertension secondary to collagen vascular disease. Hypersensitivity to the drug has not been reported. We report a case of a patient with pulmonary hypertension and undifferentiated connective tissue disease who, after 2 months of treatment with epoprostenol, presented with rapidly progressive erythema, scaling, nausea and vomiting, and fever. Test results from a skin biopsy specimen were consistent with a drug reaction. The patient' condition improved after rapid tapering of her epoprostenol and administration of corticosteroids. Epoprostenol may be associated rarely with severe erythroderma.

CD34 expression in desmoplastic melanoma

BACKGROUND

Primary and metastatic malignant melanoma can simulate various soft tissue tumors, including dermatofibrosarcoma protuberans (DFSP). Expression of CD34, a marker characteristic of DFSP, as well as other spindle cell tumors, has not been previously documented in malignant melanoma.

METHODS

We present here an unusual case of metastatic malignant melanoma with a strong histologic resemblance to DFSP and also CD34 expression.

RESULTS

The patient, a 72-year-old man with a history of an invasive malignant melanoma of the skin of the right lower abdomen, presented with a right axillary mass. Histologic sections revealed intersecting fascicles of spindle cells with nuclear pleomorphism and numerous mitotic figures, diffusely infiltrating the adipose tissue in a pattern closely simulating that seen in DFSP. In other foci, epithelioid neoplastic cells with abundant cytoplasm, prominent nucleoli, nuclear pseudoinclusions, and focal cytoplasmic melanin pigment were seen. The neoplastic spindle cells were strongly labeled by two anti-CD34 monoclonal antibodies. Some of the spindle cells and the majority of the epithelioid neoplastic cells expressed S-100 protein and focally tyrosinase. The tumor cells were negative for HMB-45 and MART-1. Melanosomes were not identified by electron microscopy.

CONCLUSION

This case demonstrates the potential of melanoma to simulate DFSP closely, on both morphologic and immunohistochemical grounds, and confirms the utility of employing a broad panel of immunohistochemical reagents in problematic cases.