Survival outcomes and prognostic factors in mycosis fungoides/Sézary syndrome: validation of the revised International Society for Cutaneous Lymphomas/European Organisation for Research and Treatment of Cancer staging proposal

PURPOSE

We have analyzed the outcome of mycosis fungoides (MF) and Sézary syndrome (SS) patients using the recent International Society for Cutaneous Lymphomas (ISCL)/European Organisation for Research and Treatment of Cancer (EORTC) revised staging proposal.

PATIENTS AND METHODS

Overall survival (OS), disease-specific survival (DSS), and risk of disease progression (RDP) were calculated for a cohort of 1,502 patients using univariate and multivariate models.

RESULTS

The mean age at diagnosis was 54 years, and 71% of patients presented with early-stage disease. Disease progression occurred in 34%, and 26% of patients died due to MF/SS. A significant difference in survival and progression was noted for patients with early-stage disease having patches alone (T1a/T2a) compared with those having patches and plaques (T1b/T2b). Univariate analysis established that (1) advanced skin and overall clinical stage, increased age, male sex, increased lactate dehydrogenase (LDH), and large-cell transformation were associated with reduced survival and increased RDP; (2) hypopigmented MF, MF with lymphomatoid papulosis, and poikilodermatous MF were associated with improved survival and reduced RDP; and (3) folliculotropic MF was associated with an increased RDP. Multivariate analysis established that (1) advanced skin (T) stage, the presence in peripheral blood of the tumor clone without Sézary cells (B0b), increased LDH, and folliculotropic MF were independent predictors of poor survival and increased RDP; (2) large-cell transformation and tumor distribution were independent predictors of increased RDP only; and (3) N, M, and B stages; age; male sex; and poikilodermatous MF were only significant for survival.

CONCLUSION

This study has validated the recently proposed ISCL/EORTC staging system and identified new prognostic factors.

Myxofibrosarcoma. Clinicopathologic analysis of 75 cases with emphasis on the low-grade variant

Myxofibrosarcoma is one of the most common sarcomas in the extremities of elderly patients. We analysed the clinicopathologic features in a series of 75 patients. All patients were adults (range, 22-91 years; median, 66 years) with an approximately equal incidence in men and women. Thirty-five tumors arose in the lower and 25 in the upper extremities, nine on the trunk, two each in the retroperitoneum and the head and neck region, and one each in the pelvis and penis. Forty-eight cases (69.5%) were located in dermal or subcutaneous tissues. Distinctive histologic features included the following: a commonly nodular growth pattern; a myxoid matrix containing elongated, curvilinear capillaries; and fusiform, round or stellate tumor cells with indistinct cell margins, slightly eosinophilic cytoplasm, and hyperchromatic atypical nuclei. These lesions varied from a hypocellular, mainly myxoid, and purely spindle-cell appearance (low-grade neoplasms) to high-grade, pleomorphic (malignant fibrous histiocytoma-like) lesions with multinucleated giant cells, high mitotic activity, and areas of necrosis. Immunohistochemistry in 44 cases revealed only vimentin and occasional actin positivity. Ultrastructurally, tumor cells had a fibroblastic phenotype. DNA flow cytometry and proliferation analysis showed an association between aneuploidy and histologic grade. An average follow-up of 45 months (range, 5-300 months) in 60 cases has revealed local recurrence in 33 cases (54%). Thirteen patients developed metastases, and 13 tumor-related deaths occurred. A short interval to first local recurrence was associated with poor clinical outcome. The rate of local recurrence was independent of histologic grade, but only intermediate and high-grade neoplasms metastasized. The depth of the primary lesion did not influence the incidence of local recurrence. However, in deep-seated neoplasms, the incidence of metastases was higher and the percentage of tumor-related deaths was twice as high as in superficially located lesions, reflecting the fact that deep-seated lesions tended to be higher-grade, larger tumors. Myxofibrosarcoma tends to become progressively higher grade in recurrences, as demonstrated in five cases in our series. The poorly recognized low-grade myxofibrosarcoma is emphasized, as proper diagnosis and treatment and scrupulous follow-up are mandatory to avoid local recurrence and gradual tumor progression to a higher-grade neoplasm that may then metastasize.

Eccrine porocarcinoma (malignant eccrine poroma): a clinicopathologic study of 69 cases

The clinicopathologic characteristics of 69 cases of eccrine porocarcinoma (EP) have been studied. Seven cases of purely in situ disease are included. Forty patients were female, 29 male with ages ranging from 29 to 91 years (mean 73 years). The lower extremity represented the single most common site (44%). Other common sites were the trunk (15 cases, 24%) and head (11 cases, 18%). The histologic diagnosis of EP was predicated on the basis of an irregular tumor at least partly formed of characteristic poromatous basaloid epithelial cells displaying ductal differentiation, and significant cytologic atypia. Forty-seven tumors (68%) contained mature well-formed eccrine ducts having an eosinophilic luminal cuticle, with the remaining tumors containing small ill-formed ducts and/or intracytoplasmic lumina. All ducts were discernible via light microscopy and in 49 cases were highlighted with DPAS stain and/or CEA/EMA immunocytochemistry. A variant with a broad pushing tumor margin and marked nuclear pleomorphism showed some resemblance to proliferative bowenoid dysplasia. In 11 cases (18%) the tumors appeared to arise in continuity with a benign preexistent poroma. A variety of histologic patterns were displayed including clear, squamous, and spindle cell differentiation, mucus cell metaplasia, and colonization by melanocytes. Lymphovascular invasion was present in 9 cases (15%). Three cases showed pagetoid extension of malignant cells (epidermotropism) and appeared to be multifocal. Follow-up was available in 54 patients (78%) with 9 (17%) experiencing local recurrence, 10 developing lymph node metastases (19%), and 6 (11%) experiencing distant metastases or death. Mitoses, the presence of lymphovascular invasion, and tumor depth >7 mm were associated with a poorer prognosis. Dividing tumors into those with a "pushing" or "infiltrating" advancing margin was also predictive of outcome with the latter having an increased risk of local recurrence. This report, the largest series of EP to date, suggests that the incidence of aggressive behavior is less than popularly believed. Furthermore, EP can display a wide variety of histologic patterns that may lead to diagnostic error in the unwary. The large number of cases in this series enables a reliable evaluation of prognostic parameters. A more aggressive clinical course may be indicated by more than 14 mitoses per high power field (hazard ratio [HR] for death 17.0, 95% confidence interval [CI] 2.71-107), lymphovascular invasion by tumor (HR 4.41, CI 1.13-17.2), and depth >7 mm (HR 5.49, CI 1.0-30.3). Thus, mitoses, lymphovascular invasion, and tumor depth should be evaluated in these tumors. We also suggest that tumors presenting an "infiltrative" advancing margin are particularly prone to local recurrence and require wide excision with close attention to the surgical margins by the reporting pathologist.

Epithelioid hemangioendothelioma of skin and soft tissues: clinicopathologic and immunohistochemical study of 30 cases

Epithelioid hemangioendothelioma of soft tissues (EHE) represents a distinct entity with an unpredictable clinical course. We analyzed the clinicopathologic and immunohistochemical features in a series of 30 patients. Patient age range was 16-74 years (median 50); 18 of 30 patients were female. Eight tumors arose in the lower and two in the upper extremities, seven on the trunk, five each in the head/ neck and anogenital regions, two in the mediastinum, and one in the abdomen. Seventeen neoplasms were located in deep soft tissues, nine were subcutaneous or perifascial, and four were dermal; size ranged from 0.4 to 10 cm; in 11 cases the tumor was > 5 cm. Tumors with an infiltrative growth pattern were more common than entirely circumscribed lesions. The tumors were composed histologically of short strands, cords, or small clusters of epithelioid, round, to slightly spindled endothelial cells that formed at least focally, intracellular lumina and were set in a frequently myxohyaline stroma. Thirteen of 30 lesions showed angiocentric growth, which was occlusive in many cases. Immunohistochemically, all cases tested were positive for at least one endothelial marker (CD31, CD34, factor VIII, Ulex europaeus), six of 23 (26%) were positive for cytokeratin, and five of 11 (45%) were positive for alpha-smooth muscle actin. Median follow-up of 36 months (range 2-96) in 24 cases showed local recurrence in three cases and systemic metastases in five cases (21%); four patients (17%) died of tumor. Although more aggressive histologic features (striking nuclear atypia in eight cases, numerous spindled cells in 10, more than two mitoses per 10 high-power fields in nine, and small, more solid angiosarcomalike foci in four cases) tended to be related to poor clinical outcome, there was no clear correlation. Two metastasizing cases showed no histologically atypical features whatever. We suggest that EHE of soft tissue is better regarded as a fully malignant, rather than borderline, vascular neoplasm, albeit the prognosis is better than in conventional angiosarcoma.

Genetic and functional analyses of FH mutations in multiple cutaneous and uterine leiomyomatosis, hereditary leiomyomatosis and renal cancer, and fumarate hydratase deficiency

Germline mutations of the fumarate hydratase (FH, fumarase) gene are found in the recessive FH deficiency syndrome and in dominantly inherited susceptibility to multiple cutaneous and uterine leiomyomatosis (MCUL). We have previously reported a number of germline FH mutations from MCUL patients. In this study, we report additional FH mutations in MCUL and FH deficiency patients. Mutations can readily be found in about 75% of MCUL cases and most cases of FH deficiency. Some of the more common FH mutations are probably derived from founding individuals. Protein-truncating FH mutations are functionally null alleles. Disease-associated missense FH changes map to highly conserved residues, mostly in or around the enzyme's active site or activation site; we predict that these mutations severely compromise enzyme function. The mutation spectra in FH deficiency and MCUL are similar, although in the latter mutations tend to occur earlier in the gene and, perhaps, are more likely to result in a truncated or absent protein. We have found that not all mutation-carrier parents of FH deficiency children have a strong predisposition to leiomyomata. We have confirmed that renal carcinoma is sometimes part of MCUL, as part of the variant hereditary leiomyomatosis and renal cancer (HLRCC) syndrome, and have shown that these cancers may have either type II papillary or collecting duct morphology. We have found no association between the type or site of FH mutation and any aspect of the MCUL phenotype. Biochemical assay for reduced FH functional activity in the germline of MCUL patients can indicate carriers of FH mutations with high sensitivity and specificity, and can detect reduced FH activity in some patients without detectable FH mutations. We conclude that MCUL is probably a genetically homogeneous tumour predisposition syndrome, primarily resulting from absent or severely reduced fumarase activity, with currently unknown functional consequences for the smooth muscle or kidney cell.

Mixed tumors and myoepitheliomas of soft tissue: a clinicopathologic study of 19 cases with a unifying concept

We report 19 unusual cases of mixed tumors and myoepitheliomas arising in soft tissues. The neoplasms occurred in 12 males and seven females. The age at diagnosis ranged from 2 to 83 years (mean 35, median 30). Eight tumors arose in the upper limb, six in the lower limb, three in the trunk, and two in the head and neck region. Three cases involved both dermis and subcutis; the remainder arose in subcutaneous (13 cases) or deep subfascial soft tissue (three cases). The most common presenting complaint was a painless swelling, with duration ranging from 2 weeks to 1 year (median 2.5 months). Microscopically, the tumors were predominantly well circumscribed and lobulated. Six cases showed a focally infiltrative margin. Cardinal morphologic features included nests, cords, and ductules of epithelioid cells and/or nests of spindled cells within a hyalinized to chondromyxoid stroma. One tumor was predominantly composed of myoepithelial cells and devoid of epithelial differentiation (i.e., ductules). Cytoplasmic hyaline inclusions were noted in two cases; squamous differentiation was seen in one case. Osteoid production and/or metaplastic bone was observed in three tumors. Chondroid differentiation (usually mature) was seen in four cases. Adipocytic differentiation was seen in two tumors. Mitotic activity was variable but generally scant; atypical mitotic figures were not identified. By immunohistochemistry, 16 of 16 cases expressed pan-keratin; 16 of 17 S-100 protein; six of 14 alpha smooth muscle actin (IA4); two of 10 muscle specific actin (HHF-35); two of 10 desmin; three of 11 glial fibrillary acidic protein; and three of 16 epithelial membrane antigen. Clinical follow-up was available in 10 patients and ranged from 6 months to 20 years (mean 4.25 years, median 2 years). Two patients developed local recurrence; metastasis to lung and lymph nodes were observed in two additional patients. Both of the latter patients died. We believe that these findings expand the concept of cutaneous mixed tumors to include neoplasms composed predominantly of myoepithelial cells and to include tumors arising in deeper subcutaneous and/or subfascial tissues. The clinical behavior of such neoplasms, when arising in soft tissues, may be difficult to predict but is most often benign; however, a minority of lesions metastasize. Until larger studies with longer follow-up are available, treatment and prognostication are probably best based on criteria used in comparable salivary gland tumors.

[18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a diagnostic tool for neurofibromatosis 1 (NF1) associated malignant peripheral nerve sheath tumours (MPNSTs): a long-term clinical study

BACKGROUND

Malignant peripheral nerve sheath tumours (MPNSTs) are difficult to detect in neurofibromatosis 1 (NF1) individuals. The purpose was to evaluate [(18)F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) and PET computed tomography (CT) as a diagnostic tool for MPNST in NF1 patients with symptomatic plexiform neurofibromas and to verify the diagnosis by pathology and clinical follow-up.

PATIENTS AND METHODS

NF1 individuals with symptomatic plexiform neurofibromas underwent clinical evaluation and magnetic resonance imaging. Qualitative FDG PET and PET CT associated with semi-quantitative maximum standard uptake value (SUVmax) assessed possible malignant change. Excision/biopsy verified the diagnosis when possible and clinical follow-up was undertaken in all patients.

RESULTS

In all, 116 lesions were detected in 105 patients aged 5-71 years, including 80 plexiform neurofibromas, five atypical neurofibromas, 29 MPNST and two other cancers. Biopsy confirmed the findings in 59 tumours and no MPNST was diagnosed on clinical follow-up of 23 lesions diagnosed as benign on FDG PET and PET CT. FDG PET and PET CT diagnosed NF1-associated tumours with a sensitivity of 0.89 [95% confidence interval (CI) 0.76-0.96] and a specificity of 0.95 (CI 0.88-0.98), but the SUVmax level did not predict tumour grade.

CONCLUSION

FDG PET and PET CT is a sensitive and specific diagnostic tool for NF1-associated MPNST. Other PET tracers will be required to solve the problem of predicting tumour grade.

Infantile hemangiopericytoma versus infantile myofibromatosis. Study of a series suggesting a continuous spectrum of infantile myofibroblastic lesions

The clinicopathologic features of 11 tumors, originally diagnosed as infantile hemangiopericytomas and with a spectrum of morphologic findings, are described. The age of the patients ranged from 6 days to 7 years; seven patients were younger than 1 year (mean, 2.25 years; median, 10 months); six were boys and five were girls. Three neoplasms were situated in skin or subcutis and seven in deep soft tissue; in one case the depth was unstated. Seven lesions arose in the lower limbs, and one each in the lumbar region, clitoris, chest wall, and soft tissue of the zygomatic region. One patient later was found to have two additional dermal tumors, one each on the anterior abdominal wall and the chest wall. Follow-up information in eight patients revealed local recurrence 12 years later in one case only. Histologically, all tumors showed distinctive features of infantile hemangiopericytoma, including immature cytology, multilobulated growth pattern, focal necrosis, and mitotic activity in varying degrees. Vascular invasion was noted in seven cases. Additionally, a second tumor cell component, composed of spindle-shaped myofibroblastic cells forming fascicles and micronodules, was evident at least focally. Both the spindle cells and more primitive round cells were positive for alpha-smooth muscle actin. Both cellular components showed a haphazard zoning arrangement. We discuss the clinicopathologic similarities between infantile hemangiopericytoma and infantile myofibromatosis and point out the differences between infantile and adult hemangiopericytoma. Our study suggests that there exists a broad spectrum of benign infantile myofibroblastic lesions containing an immature-appearing cellular component with a distinctive, hemangiopericytoma-like vascular pattern. Infantile myofibromatosis and so-called infantile hemangiopericytoma almost certainly represent different stages of maturation of the same (single) entity.

Melanoma associated with blue nevus and melanoma mimicking cellular blue nevus: a clinicopathologic study of 10 cases on the spectrum of so-called 'malignant blue nevus'

The term "malignant blue nevus" refers to a rare and heterogeneous group of melanomas that arise in several clinical settings. This includes melanomas arising in association with a common or cellular blue nevus and those arising de novo and resembling cellular blue nevi. We reviewed the clinicopathologic features of 10 cases of malignant blue nevi. Six cases proved to be de novo melanoma mimicking cellular blue nevus, but lacking a clear-cut benign component. Two melanomas arose in association with a common blue nevus, and two with a cellular blue nevus. The patients' (5 males, 5 females) ages ranged from 11 to 77 years (average age, 48.1 years). The head and neck was the most common location (6 of 10 patients), with five scalp tumors. Four tumors were located on the trunk; none was located on the extremities. Tumor size ranged from 0.5 to 2.2 cm (average size, 1.1cm). Most lesions had been present for many years before surgical removal. Pigmented dendritic cells were observed in 9 of 10 cases. The malignant and benign components were easily distinguished in the four cases that arose in association with a common or cellular blue nevus. Abrupt transition between a benign blue nevus and melanoma was readily recognized at scanning magnification as distinctive nodules of epithelioid to spindled cells with a sheet-like growth pattern. In all cases, malignancy was evidenced by increased mitotic rate, necrosis, nuclear atypia, pleomorphism, hyperchromasia, and prominent nucleoli. All 7 patients with follow-up information experienced recurrence (3 patients) or metastasis (4 patients). Three patients died of disease. Malignant blue nevus is a heterogeneous group of melanomas that are highly aggressive and often lethal, with a propensity for metastasis to the lymph nodes and lungs.

Cutaneous rosai-dorfman disease is a distinct clinical entity

Rosai-Dorfman disease (RDD) is a rare but distinctive clinicopathologic entity of unknown etiology affecting lymph nodes as well as extranodal sites. Although cutaneous involvement in RDD is common, purely cutaneous disease is rare and not well documented. We report 22 patients with cutaneous and superficial subcutaneous RDD. The lesions presented as papules and nodules, often with discoloration (9/22) and frequent multifocality (13/22), without predilection for a specific site of the body. Age distribution was wide and ranged from 15 to 68 years, with a median of 43.5 years. Of the 17 patients for whom information on racial background was available, 7 were Asian, 8 were white, and 2 were black, with a marked female predominance (2:1). The lesions resolved in 6 of 13 patients for whom follow-up data were available, regardless of the treatment given. Lesions persisted or recurred in 7 patients. Histologically, the lesions are invariably characterized by a proliferation of polygonal S100-positive histiocytes showing emperipolesis and a mixed inflammatory infiltrate. This study characterizes the histologic spectrum of cutaneous RDD in regard to variation in the numbers of typical S100-positive histiocytes and emperipolesis, variation in the quality and quantity of the inflammatory response, and the degree of stromal fibrosis, which resulted in a strikingly storiform growth pattern in six lesions and a lobulated pattern in two lesions. Whereas the clinical as well as histologic appearance of the cutaneous and subcutaneous lesions in the purely extranodal forms of RDD is indistinguishable from that of systemic RDD, this study emphasizes that purely cutaneous RDD is a distinct clinical entity in regard to its epidemiology and remains localized to the skin even with long-term follow-up. Patients with purely cutaneous RDD are of an older age at onset of disease (median = 43.5 years), with a reversed male/female ratio. There are no significant systemic extracutaneous or serologic manifestations. Whereas systemic RDD is commonly seen in blacks and only rarely reported in Orientals, the majority of the patients in this series with purely cutaneous RDD are Asians and whites.

Spitz tumors in children: a grading system for risk stratification

OBJECTIVE

To describe a grading system for risk stratification of atypical Spitz tumors in children and adolescents. In some circumstances, unequivocal distinction between Spitz nevus and melanoma is practically impossible. It is likely that these lesions for which we lack specific diagnostic criteria represent a broad histological continuum extending from benign to malignant tumors. Therefore, we propose that Spitz tumors be categorized into low-, intermediate-, or high-risk categories based on the accumulation of abnormal features.

DESIGN

Retrospective study.

SETTINGS

Institutional practice.

PATIENTS

We present 30 cases of atypical Spitz tumors in patients younger than 18 years evaluated for at least 3 years or in whom a metastatic event developed during this period.

INTERVENTION

None.

MAIN OUTCOME MEASURE

The grading system was formulated after data collection.

RESULTS

Among the parameters studied, only diagnosis at age greater than 10 years, diameter of the lesion greater than 10 mm, presence of ulceration, involvement of the subcutaneous fat (level V), and mitotic activity of at least 6/mm2 carried a likelihood ratio greater than 1.50 and were therefore used for the grading system.

CONCLUSION

The application of an objective grading system, such as the one described herein for the first time, is the first step in providing useful information for the management of atypical Spitz tumors.

Clinical features of multiple cutaneous and uterine leiomyomatosis: an underdiagnosed tumor syndrome

OBJECTIVE

To investigate the clinical features of the multiple cutaneous and uterine leiomyomatosis (MCUL) syndrome, including the hereditary leiomyomatosis and renal cell cancer syndrome.

DESIGN

A case series of patients with multiple skin leiomyomas solicited via a circular letter to dermatologists.

SETTING

Research institute.

PATIENTS

A total of 108 affected individuals, including 46 probands and 62 affected relatives.

MAIN OUTCOME MEASURES

The proportion of probands with underlying fumarate hydratase (FH) mutations, the penetrance of FH mutations, and clinicopathologic features of MCUL.

RESULTS

Forty-one (89%) of 46 probands with multiple skin leiomyomas had evidence of germline FH mutations, which were highly penetrant. All 26 male mutation carriers had skin leiomyomas. Of 67 women with FH mutations, 46 (69%) had both skin and uterine leiomyomas; 10 (15%) had only skin leiomyomas; 5 (7%) had only uterine leiomyomas; and 6 (9%) were clinically unaffected. Patients presented with skin leiomyomas at a mean age of 24 years and had a mean of 25 lesions. Forty-one individuals (89%) reported painful lesions, particularly in response to cold or trauma. Fibroids were histologically unremarkable, highly symptomatic, and associated with a high risk of early hysterectomy. One individual had a very aggressive collecting duct renal cancer. The G354R FH mutation predisposed patients to uterine fibroids without skin leiomyomas (P = .03). Many patients with skin leiomyomas had not previously presented for medical attention. Fibroids were rarely recognized as cases of MCUL.

CONCLUSIONS

Highly penetrant FH mutations underlie MCUL. Increased clinical awareness is important because of the associated risk of severe uterine fibroids and, in some cases, aggressive renal cancer.

Superficial angiomyxoma: clinicopathologic analysis of a series of distinctive but poorly recognized cutaneous tumors with tendency for recurrence

Despite being first described in 1988, superficial angiomyxoma is still a poorly recognized cutaneous tumor. Although its histologic features are distinctive, its existence seems not to be widely accepted. We analyzed the clinicopathologic and immunohistochemical features in a series of 39 cases. Twenty-five patients were males; age range was birth to 82 years (median, 45.5 years). Most cases presented as cutaneous papules, nodules, or polypoid lesions. Seventeen tumors arose on the trunk, 14 on the head and neck, and seven on the lower limbs. All cases were treated by local excision, and eight recurred locally. In four of the latter cases, there were two recurrences. Histologically, the lesions were dermal with variable involvement of the subcutis. Tumors were poorly circumscribed, but a focal lobular outline was always identified. Distinctive histologic features included extensive myxoid stroma, numerous small blood vessels, varying cellularity, acellular mucin pools, stellate or bipolar fibroblastic cells, muciphages, a sparse, mixed inflammatory cell infiltrate with notable neutrophils, and occasional plumper cells with eosinophilic cytoplasm. Cytologic atypia was mild at most, and mitotic figures were rare. In approximately 20% of cases, the primary lesion or its recurrence contained epithelial structures, including epidermoid cysts, thin strands of squamous epithelium, and small buds of basaloid cells. Immunohistochemically, tumor cells were negative for S-100 protein, smooth muscle actin, and pan-keratin. We support the concept of superficial angiomyxoma as a distinctive clinicopathologic entity that should be included in the differential diagnosis of other myxoid cutaneous tumors, including dermal nerve sheath myxoma, trichodiscoma and trichofolliculoma, and low-grade myxofibrosarcoma.

Lipoblastoma and lipoblastomatosis: a clinicopathological study of 14 cases

The clinicopathological features of 14 cases of lipoblastoma and lipoblastomatosis are presented. The age of the patients at presentation ranged from 5 days to 6 years (mean 2.7 years); nine patients were male. Histologically, six cases were circumscribed (lipoblastoma) while eight were diffuse and ill-defined (lipoblastomatosis). In both groups and in individual cases there was distinct lobulation, as well as a spectrum of adipocytic maturation. Cytologically, the 10 most mature lesions were composed of uniform adipocytes intermixed with only scattered lipoblasts and primitive mesenchymal cells. A notable feature in the other four cases was a prominent myxoid stroma producing a very close resemblance to myxoid liposarcoma. Mitotic figures were rare and always normal in appearance. Atypical nuclei were not evident. Follow-up in eight patients revealed local recurrence in two. Liposarcoma in patients under 10 years is exceedingly rare, and, in myxoid form, may be almost impossible to distinguish histologically from lipoblastoma. Helpful clues are the lack of lobulation, variable growth pattern and increased nuclear atypia in liposarcoma.

Pilomatrix carcinomas contain mutations in CTNNB1, the gene encoding beta-catenin

Mutations in beta-catenin are present in benign pilomatrixomas. beta-catenin is a downstream effector in the WNT-signalling pathway, acting as a signal for differentiation and proliferation. Mutations in CTNNB1, the gene encoding beta-catenin, are present in a wide variety of benign and malignant neoplasms. We examined beta-catenin in a series of pilomatrix carcinomas (15 cases) by using immunohistochemistry and DNA sequencing of exon 3 from CTNNB1, and compared these to a series of benign pilomatrixomas (13 cases). All 11 pilomatrix carcinomas available for examination showed nuclear localization of beta-catenin and mutations in exon 3 similar to those demonstrated in benign pilomatrixomas. Two of 11 pilomatrix carcinomas showed significant nuclear accumulation of p53, whereas this was absent in all 13 benign pilomatrixomas. Expression of nuclear cyclin D1 was similar in both benign pilomatrixomas and pilomatrix carcinomas. Clinical follow-up from the 15 malignant cases reported in this study and by others indicates that wide excision offers superior control of local recurrence, compared to simple excision. Immunohistochemical and molecular analysis of beta-catenin reveals that both pilomatrix carcinomas and benign pilomatrixomas harbour mutations in beta-catenin. This implies a common initial pathogenesis and is compatible with the proposition that pilomatrix carcinomas may at least on occasion arise from their benign counterparts.

Epithelioid benign fibrous histiocytoma of skin: clinico-pathological analysis of 20 cases of a poorly known variant

Twenty new cases of epithelioid fibrous histiocytoma, a distinctive but poorly recognized variant of cutaneous benign fibrous histiocytoma are described. Twelve patients were male and eight were female. The age of the patients ranged from 7 to 80 years (median 40 years). Six lesion arose on the lower limb, five on the upper limb, three around the shoulder, two on the abdomen and one each on the eyelid, inner canthus and anal margin. In one case the age and site were not stated. All lesions presented as a solitary, polypoid or slightly raised cutaneous nodule, ranging in size from 0.5 cm to 2 cm in greatest diameter. Follow-up in 14 cases (mean 22.7 months) revealed local recurrence after 42 months in one case. Histologically, the more polypoid tumours were characterized by an epidermal collarette. In all lesions prominent polygonal or rounded epithelioid cells with abundant eosinophilic cytoplasm, a vesicular nucleus and small eosinophilic nucleoli accounted for at least 50% of the tumour cell population. Individual cells were separated by somewhat hyalinized collagen, containing prominent blood vessels and a sparse mononuclear inflammatory cell infiltrate. The edge of the lesions, especially those that were non-polypoid, often showed more typical features of ordinary fibrous histiocytoma. The main differential diagnosis is with other cutaneous epithelioid neoplasms, especially Spitz naevus.

[18F]FDG PET/CT in the diagnosis of malignant peripheral nerve sheath tumours in neurofibromatosis type-1

PURPOSE

The detection of malignant peripheral nerve sheath tumours (MPNSTs) in patients with neurofibromatosis 1 (NF1) remains a clinical challenge. The purpose of this study was to evaluate the use of [(18)F]2-fluoro-2-deoxy-D-glucose PET/CT (FDG PET/CT with early and delayed imaging) in patients with symptomatic neurofibromas, to revalidate current cut-off values for identification of malignant change within neurofibromas and to examine the relationship between SUV and tumour grade.

METHODS

Patients with symptomatic neurofibromas underwent FDG PET/CT imaging at 90 and 240 min. Semiquantitative analysis using maximum standardized uptake value (SUVmax) was performed and correlated with histology.

RESULT

In 69 patients, 85 lesions were identified for analysis, including 10 atypical neurofibromas and 21 MPNSTs. Sensitivity of FDG PET/CT in diagnosing NF1-associated MPNST was 0.97 (95% CI 0.81-0.99) and the specificity was 0.87 (CI 0.74-0.95). There was a significant difference in SUVmax between early and delayed imaging and in SUVmax between tumours identified as benign and malignant on PET/CT. There was also a significant difference in SUVmax between tumour grades.

CONCLUSION

FDG PET/CT is a highly sensitive and specific imaging modality for the diagnosis of MPNST in NF1 patients. We recommend performing early (90 min) and delayed imaging at 4 h for accurate lesion characterization and using a cut-off SUVmax of 3.5 on delayed imaging to achieve maximal sensitivity.

Cutaneous pilar leiomyoma: clinicopathologic analysis of 53 lesions in 45 patients

As cutaneous pilar leiomyomas have received little attention in the recent literature, 53 lesions from 45 patients were studied to analyze their clinicopathologic features. There was an equal distribution between both sexes; most patients were adults with a wide age distribution. Both multiple (29 lesions from 21 patients) and solitary tumors (18 patients) were included. Lesions on the extremity (29 tumors) were common in both groups, whereas truncal tumors (11) were confined largely to patients with multiple lesions. In six patients the number of lesions was not specified. The tumors were painful in 17 patients. Three patients had a positive family history of similar lesions. Histologic study revealed ill-defined bundles of well-differentiated smooth muscle cells in the reticular dermis in all cases, although nine lesions had a more nodular pattern. Overlying epidermal hyperplasia was noted in 29 cases (54.7%). Immunohistochemically there appeared to be an increased number of nerve fibers within and surrounding the tumors. Mitotic activity was observed in 15 lesions (28.3%), 13 of which had <1 mitosis per 10 high power fields (HPF); the remaining two lesions had 1-2 mitoses per 10 HPF. Follow-up was available in 10 of these mitotically active tumors and ranged from 9 months to 7 years. There was no recurrence in any of them. We have concluded tentatively that leiomyomas of arrector pili origin may exhibit a low mitotic activity of <1 per 10 HPF and that this does not adversely affect the prognosis for these patients.

Malignant eccrine spiradenoma (spiradenocarcinoma): a clinicopathologic study of 12 cases

Malignant eccrine spiradenoma is a very rare tumor. The clinicopathologic features of 12 cases are reported herein. Six patients were men, six were women, and the average patient age was 62 years. Seven tumors were located on the trunk, three on the extremities, and two in the head and neck region. All tumors were large (average size-7.5 cm). Lesions had been present from 7 months to 30 years before surgical removal. In all cases, continuity between benign eccrine spiradenoma and areas with malignant change was observed. Malignancy was evidenced by increased mitotic rate, necrosis, nuclear atypia, pleomorphism, and hyperchromasia, loss of nested and trabecular growth patterns, and absence of a dual cell population. In most cases (8 of 12), the malignant component comprised the bulk of the lesion. Two distinctive histologic patterns were observed. Five of 12 tumors exhibited abrupt transition between a benign eccrine spiradenoma and a high-grade carcinoma component. The others lacked a clear-cut transition between benign and malignant components and were diagnostically challenging. Diagnosis in such cases was established based on the loss of two cell populations, increased nuclear to cytoplasmic ratio, hyperchromasia, and marked mitotic activity. Two tumors showed focal squamous differentiation. Five of seven patients on whom there was follow-up information were free of disease (average duration of follow-up = 3.4 years). One patient developed metastases to local lymph nodes 5 years after the primary tumor was resected. This patient had no evidence of disease 16 months after resection of her lymph node metastases.

Frequent abnormalities of the p15 and p16 genes in mycosis fungoides and sezary syndrome

There are few data on the molecular pathogenesis of cutaneous T cell lymphomas. A recent allelotyping study by our group identified frequent allelic loss on 9p, 10q, and 17p including losses on 9p21 in 16% of patients with mycosis fungoides and 46% with Sezary syndrome. The P15 and P16 genes are intricately linked on 9p21 and can be inactivated in melanoma and non-Hodgkin's lymphoma. We have therefore studied 76 patients with either mycosis fungoides or Sezary syndrome for abnormalities of these genes. DNA samples were analyzed for loss of heterozygosity, homozygous deletion, intragenic mutations, and promoter methylation. In addition P15 and P16 protein expression was assessed. Microsatellite analysis was informative in 73 of 76 cases: allelic loss on 9p21 was identified in 18 patients (25%), including 12 of 57 with mycosis fungoides (21%) and six of 16 with Sezary syndrome (37%). Single strand conformation polymorphism analysis of the entire coding regions of both genes did not identify any mutations, although two polymorphisms were identified including C613A, which has not previously been described. P15 and P16 gene promoter methylation was found in 45% and 29% of patients, respectively. Furthermore aberrant P15 protein expression was detected in 85% of patients analyzed with P15 gene abnormalities and abnormal P16 expression in 59% with P16 gene abnormalities. These abnormalities were not dependent on cutaneous stage of disease. This study suggests that abnormalities of the P15 and P16 genes are common in both early and advanced stages of mycosis fungoides and Sezary syndrome and that these genes may be inactivated by allelic loss and aberrant promoter methylation.

Aneurysmal benign fibrous histiocytoma: clinicopathological analysis of 40 cases of a tumour frequently misdiagnosed as a vascular neoplasm

Forty cases of the distinctive but poorly recognized aneurysmal variant of cutaneous fibrous histiocytoma are described. These tumours presented most commonly in middle-age adults, with a slight predilection for females. Anatomical distribution was wide with most cases occurring in the lower limb/limb girdle (50%), upper limb/limb girdle (20%) and trunk (17%). Lesional size ranged from 0.5 cm to 4 cm. Haemorrhage accounted for the rapid clinical growth of some lesions and the frequent clinical confusion with a cyst, a melanocytic lesion or a haemangioma. Five (19%) of the twenty-six cases with follow-up (mean duration 2.5 years) recurred locally, twice in two cases. One of these cases had involvement of a regional lymph node in the second recurrence, most likely as a result of direct local extension. Distinctive histological features were prominent blood-filled spaces, varying from artefact-like clefts to cystic areas mimicking cavernous vascular channels but devoid of an endothelial lining, prominent haemosiderin deposition, numerous siderophages and giant cells, and a moderate mitotic rate. Despite the presence of prominent secondary changes due to haemorrhage, all cases showed cellular polymorphism, hyalinized collagen bundles surrounded by tumour cells in the periphery of the lesion and 88% showed some degree of epidermal hyperplasia, as seen in common fibrous histiocytoma. Immunohistochemistry (ABC method) revealed only vimentin and, rarely, focal smooth muscle actin positivity. CD68 was positive in some reactive macrophages only. Stains for CD31, CD34, desmin and factor XIIIa were negative in all cases tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of Positron Emission Tomography Scanning and Sentinel Node Biopsy in the Detection of Micrometastases of Primary Cutaneous Malignant Melanoma

PURPOSE: Sentinel node biopsy (SNB) is a surgical technique for detecting micrometastatic disease in the regional draining nodes. 2-fluorine-18-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scanning is an imaging technique that can detect clinically undetectable metastases. This prospective study was undertaken to compare the sensitivity of FDG-PET scanning with SNB in the detection of micromatastatic malignant melanoma.

PATIENTS AND METHODS: Fifty consecutive patients (23 women, 27 men; mean age, 53 years) with primary melanoma >1 mm thick or lymphatic invasion were recruited (mean, 2.41 mm). Primary lesions had been narrowly excised (<1 cm). Patients underwent PET scanning followed by SNB, using a dual technique. Preoperative lymphoscintigraphy was used to identify the draining basin. Lymph nodes were examined histologically and immunostained for S100 and HMB 45.

RESULTS: The sentinel node (SN) was identified in all patients. Fourteen patients (28%) had positive SNBs, including eight patients with melanoma <1.5 mm thick. In none of these 14 patients did PET scans identify metastatic disease in the SN or draining basin. In seven patients, the PET scans were positive in other locations, and in four cases, this was suspicious of metastatic disease. However, no patient has developed recurrent melanoma (mean follow-up, 15 months). All patients with positive SNBs underwent therapeutic lymph node dissection. Further lymph node involvement was found in two patients (primary lesions, 1.3 mm and 3.5 mm thick).

CONCLUSION: This study demonstrates the limitations of FDG-PET scanning in staging patients with primary melanoma. SNB is the only reliable method for identifying micrometastatic disease in the regional draining node.

Morphological and immunohistochemical characteristics of atypical fibroxanthoma with a special emphasis on potential diagnostic pitfalls: a review

The present manuscript gives emphasis on recognizing different morphological variants of atypical fibroxanthoma (AFX), on validation of immunohistochemical markers and on discussing potential diagnostic pitfalls.

MATERIAL AND METHODS

Histological features analyzed in 66 AFXs were: ulceration, morphological variants, growth pattern, location in the skin and vascular/perineural invasion. The antibodies used were CK-MNF116, CK-AE1/AE3, S100, smooth muscle actin, desmin, CD31 and EMA.

RESULTS

The study included 59 males, 7 females, aged 55-95 years, mean 77 years. All developed on sun damaged skin. Ulceration was present in 50%. Morphological patterns were pleomorphic spindle and epithelioid cells (60.6%), predominantly spindle cells (19.7%), purely spindle-cells (13.6%), and predominantly epithelioid cells (6.1%). Most were localized in the dermis (57.6%). An expansile (36.4%) rather than infiltrative (6.1%) growth into superficial subcutis was also noted. No vascular/perineural invasion was seen. Additional changes were hemorrhagic and pseudoangiomatous areas (24.2%), granular cell change (22.7%), keloid-like areas (9.1%), myxoid change (7.6%), osteoclast-like giant cells (6.1%) and clear cell change (4.6%). AFXs were consistently negative for S100, CK-MNF116, CK-AE1/AE3 and desmin. Focal positivity for SMA (45.2%), EMA (24.4%) and CD 31 (9.5%) was seen.

CONCLUSIONS

A diagnosis of AFX is still made by exclusion of other malignant neoplasms with similar morphology. Immunohistochemistry plays a crucial role in this distinction, but can also be misleading. This study expands the spectrum of non-vascular CD31 positive tumors.

Absence of the t(14;18) chromosomal translocation in primary cutaneous B-cell lymphoma

BACKGROUND

The t(14;18)(q32;q21) chromosomal translocation is found in the majority of nodal follicular lymphomas and in a lower percentage of systemic high-grade diffuse large B-cell lymphomas. The translocation results in the juxtaposition of the bcl-2 gene on chromosome 18 with the immunoglobulin heavy chain joining region on chromosome 14. Bcl-2 protein prevents apoptosis and the translocation leads to overexpression of a functionally normal Bcl-2 protein that prevents apoptosis of neoplastic cells.

OBJECTIVES

The purpose of our study was to analyse cases of primary cutaneous B-cell lymphoma (PCBCL) for the presence of the t(14;18) translocation and to correlate the results with Bcl-2 expression and histological subtype.

METHODS

Forty-four cutaneous B-cell lymphoid proliferations (36 PCBCL, four follicular B-cell lymphomas with cutaneous presentation and four reactive B-cell infiltrates) were analysed by polymerase chain reaction amplification and polyacrylamide gel electrophoresis using consensus primers for the joining region on the immunoglobulin heavy chain gene in combination with either a primer for the major breakpoint region (MBR) or the minor cluster region (mcr) on chromosome 18.

RESULTS

None of 36 PCBCL analysed demonstrated a t(14;18) translocation; however, three of four systemic follicular B-cell lymphomas presenting in the skin were found to have a translocation in the MBR, which was confirmed by sequence analysis. Correlation with Bcl-2 immunostaining showed that of seven patients with high-grade cutaneous diffuse large B-cell lymphoma, four were Bcl-2 positive but had no evidence of a t(14;18) translocation. In the five cases classified as primary cutaneous follicle centre cell lymphoma, the neoplastic cells within the germinal centres failed to express Bcl-2. However, Bcl-2-positive neoplastic cells were present in all four cases of systemic follicular lymphoma, including the case that did not show a t(14;18) translocation. In all cases of marginal zone lymphoma the marginal zone lymphocytes were Bcl-2 positive.

CONCLUSIONS

These findings indicate that the t(14;18) translocation does not occur in PCBCL, which suggests the involvement of different pathogenetic mechanisms compared with their nodal counterparts. Furthermore, the detection of a t(14;18) translocation in cutaneous B-cell lymphoma should suggest the presence of systemic disease, which underlies the need for exhaustive staging procedures.