Photoelectric property degradation of graded barrier InAs/GaSb type II superlattice long-wave infrared detectors under 1†MeV electron irradiation.

Amid rapid advancements in aerospace science and technology, studying the effects of space radiation on an infrared detector is crucial for enhancing their reliability in radiation environments, particularly against electrons-one of the most damaging charged particles. Barrier structures significantly reduce dark current without any substantial degradation in the optical performance of the devices. Consequently, they are being investigated for use in extreme environments. This paper presents a study on the performance degradation of InAs/GaSb type II superlattice (T2SLs) long-wave infrared (LWIR) detectors with a graded barrier structure under 1 MeV electron irradiation and analyzes potential damage mechanisms. The findings indicate that 1 MeV electron irradiation causes both ionization and displacement damage to the graded barrier InAs/GaSb T2SL LWIR detectors. After irradiation with a fluence of 2 × 1015 e/cm2, the device's dark current density has increased by approximately two orders of magnitude, while the quantum efficiency has decreased by approximately one order of magnitude. As the device mesa shrinks, the sensitivity of dark current to radiation exposure increases. Electron irradiation notably exacerbates surface leakage and bulk dark current, with a pronounced increase in surface leakage current. The study also reveals that electron irradiation primarily enhances the dark current by introducing defect states, thereby leading to device performance degradation.

2 MeV proton irradiation effect on the performance of InAs/GaSb type-II superlattice long-wave infrared detectors.

In this work, we investigated the effect of 2 MeV proton irradiation on the performance of InAs/GaSb type-II superlattice long-wave infrared detectors by combining ground-based irradiation experiments with Stopping and Range of Ions in Matter (SRIM) computer simulations. We found that irradiation with 2 MeV protons significantly increases the dark current density of the detector by more than two orders of magnitude. At the same time, the quantum efficiency decreases by an order of magnitude. Moreover, proton irradiation degrades the device's performance by raising bulk and surface leakage currents. As the mesa size of the device increases, the proportion of surface leakage current in the total dark current drops. When the mesa size is smaller, the detector irradiation damage is greater. In addition, simulations indicate that the amount of damage produced by 2 MeV proton irradiation rises as irradiation fluences increase. The trends of the irradiation damage produced by the SRIM simulation results and the photocurrent measurements after proton irradiation are consistent, whereas the dark current measurements are identical only at small fluences.

K2Sr4(PO3)10: A Polyphosphate with Deep-UV Cutoff Edge and Enlarged Birefringence.

A new polyphosphate K2Sr4(PO3)10 is synthesized by a high-temperature solution method. This compound crystallizes in the triclinic space group of P1̅, consisting of the 1D infinite [PO3]∞ chains and K and Sr ions between the chains. Compared with AM2(PO3)5 (A = K, Rb, Cs; M = Ba, Pb), K2Sr4(PO3)10 exhibits a more complex [PO3]∞ chain structure and more diverse metal cationic coordination environment. More importantly, K2Sr4(PO3)10 has both a deep-UV cutoff edge (<200 nm) and a significantly enlarged birefringence. First-principles calculations indicate that the birefringence of K2Sr4(PO3)10 is 0.017 at 1064 nm, about 2 times that of RbBa2(PO3)5 (0.008 at 1064 nm), which reaches a new height among the reported mixed alkali metal and alkaline earth metal phosphate. Theoretical calculations and structural analyses show that the enlarged birefringence of K2Sr4(PO3)10 mainly originates from the [PO3]∞ chains arranged in an inverted zigzag. This discovery introduces a new strategy for devising novel phosphate deep-UV optical crystals with a large birefringence.

Transparent dual-band ultraviolet photodetector based on graphene/p-GaN/AlGaN heterojunction.

Versatile applications have driven a desire for dual-band detection that enables seeing objects in multiple wavebands through a single photodetector. In this paper, a concept of using graphene/p-GaN Schottky heterojunction on top of a regular AlGaN-based p-i-n mesa photodiode is reported for achieving solar-/visible-blind dual-band (275 nm and 365 nm) ultraviolet photodetector with high performance. The highly transparent graphene in the front side and the polished sapphire substrate at the back side allows both top illumination and back illumination for the dual band detection. A system limit dark current of 1×10-9 A/cm2 at a negative bias voltage up to -10 V has been achieved, while the maximum detectivity obtained from the detection wavebands of interests at 275 nm and 365 nm are ∼ 9.0 ×1012 cm·Hz1/2/W at -7.5 V and ∼8.0 × 1011 cm·Hz1/2/W at +10 V, respectively. Interestingly, this new type of photodetector is dual-functional, capable of working as either photodiode or photoconductor, when switched by simply adjusting the regimes of bias voltage applied on the devices. By selecting proper bias, the device operation mode would switch between a high-speed photodiode and a high-gain photoconductor. The device exhibits a minimum rise time of ∼210 µs when working as a photodiode and a maximum responsivity of 300 A/W at 6 µW/cm2 when working as a photoconductor. This dual band and multi-functional design would greatly extend the utility of detectors based on nitrides.

Primary cutaneous adenoid cystic carcinoma: a clinicopathologic, immunohistochemical, and fluorescence in-situ hybridisation study of 13 cases.

AIMS: This study aimed to investigate the clinical, histological, immunohistochemical and chromosomal features of primary cutaneous adenoid cystic carcinoma (PCACC). METHODS AND RESULTS: We retrospectively analysed 13 cases identified on their clinicopathological features and performed fluorescence in-situ hybridisation (FISH) on six available cases. Head and neck (46.2%) were most commonly involved. The median age was 53 years, with a male predilection. Histologically, tumours were classified as grades 1 (eight), 2 (four) and 3 with high-grade transformation (HGT) (one). The HGT component was demonstrated as poorly differentiated carcinoma with multifocal necrosis and myoepithelial differentiation. Patients with one of the following factors: longest diameter of the lesion (≥ 1 cm), involvement of subcutaneous fat tissue and widely infiltrative border had a relatively higher rate of local recurrence, distant metastasis and death. Five of six cases were confirmed to have MYB translocation, while nuclear staining for MYB proto-oncogene, transcription factor (MYB) protein was found in four cases. During the follow-up (median = 64 months), two patients experienced local recurrences. One patient, who was classified as grade III PCACC with HGT, developed multiple metastases and died of disease. Another patient was alive with multiple metastases. CONCLUSIONS: This is the largest single-institution study, to our knowledge, of PCACC in an Asian population. We describe the first case of scalp PCACC with HGT, which is the only death case in our series. PCACC tends to recur locally and has metastatic potential. PCACC with HGT has a poor prognosis.

Clinicopathological, immunohistochemical and fluorescence in-situ hybridisation features of early subungual melanoma: an analysis of 65 cases.

AIMS: Very limited data are available concerning the clinicopathological and molecular features of early subungual melanoma (SM), especially with regard to the Asian population. The aim of this study was to investigate the clinical, histological, immunohistochemical and chromosomal features of early SM. METHODS AND RESULTS: Fifty-two in-situ and 13 thin (Breslow thickness ≤1.0 mm) SM cases were retrospectively reviewed. All patients presented with longitudinal melanonychia involving a single digit, and the thumb was the most affected digit (35 of 65, 53.8%). Microscopically, most cases showed small to medium nuclear enlargement (58 of 65) and mild to moderate nuclear atypia (57 of 65). Hyperchromatism and irregular contours of nuclei were persistent features in all cases. The variation of melanocyte count (the number of melanocytes per mm dermal-epithelial junction) ranged from 31 to 255. Intra-epithelial mitoses were identified in 34 cases (52.3%). Statistically, features of in-situ lesions including higher melanocyte count (>70), presence of multinucleated melanocytes, inflammatory infiltrate and cutaneous adnexal extension, were associated with early invasion. Melan-A, human melanoma B (HMB)45, mouse monoclonal melanoma antibody (PNL2) and SOX10 antibodies (>95.0%) showed superior diagnostic sensitivity to S-100 protein (83.1%). Fluorescence in-situ hybridisation (FISH) results were positive in 15 of 23 successfully analysed cases. CONCLUSIONS: To the best of our knowledge, this is the largest single-institution study of early SM in an Asian population, and the largest cohort tested by FISH. Early SM mainly showed small to medium nuclear enlargement and mild to moderate nuclear atypia. High melanocyte count, hyperchromatism and irregular contours of nuclei and intra-epithelial mitoses are crucial diagnostic parameters. Immunohistochemistry, especially SOX10 staining, and FISH analysis are valuable in the diagnosis of SM.

Clinicopathological diversity and outcome of longitudinal melanonychia in children and adolescents: analysis of 35 cases identified by excision specimens.

AIMS: Longitudinal melanonychia in paediatric patients often represents a difficult diagnostic challenge, and studies emphasising its clinical and histopathological features are limited due to its low incidence in childhood. METHODS AND RESULTS: We retrospectively analysed 35 paediatric cases identified by excision specimens on their clinicopathological features, and performed fluorescence in-situ hybridisation on 13 available cases. Fingernails (77.1%) were more likely to be affected. Total melanonychia and Hutchinson's sign were observed in 10 (28.6%) and 14 (40.0%) cases, respectively. Nail dystrophy at diagnosis was present in five cases. After complete excision of the lesions, four patients relapsed during follow-up (mean = 38 months). Seventeen cases were diagnosed as lentigines and 18 as naevi, among which 11 cases were categorised as lentigines/naevi with atypical melanocytic hyperplasia. Mild-to-moderate nuclear atypia, confluency of melanocytes, focal pagetoid spread and peri-ungual skin involvement were found in 25.7% (9 of 35), 40.0% (14 of 35), 40.0% (14 of 35) and 40.0% (14 of 35) of cases, respectively. Thirteen cases tested by fluorescence in-situ hybridisation showed no copy number aberration at the probed loci. There was a statistically significant difference in the following features between patients aged less and more than 10 years (P < 0.05): cytomorphology, mild-to-moderate nuclear atypia, confluency of melanocytes, focal pagetoid spread and melanocyte count. CONCLUSIONS: Some concerning clinicopathological characteristics, which are signs indicative of melanoma in adults, are not uncommon in paediatric longitudinal melanonychia, especially in patients aged ≤ 10 years. Owing to the extremely low incidence of melanoma in paediatric longitudinal melanonychia, in most circumstances a more conservative clinical management strategy should be adopted.

Syringocystadenocarcinoma papilliferum: Clinicopathologic analysis of 10 cases.

BACKGROUND: Syringocystadenocarcinoma papilliferum (SCACP) is an exceedingly rare cutaneous adnexal neoplasm. We aimed to investigate the clinicopathologic and immunophenotypic features of SCACP, and to discuss the prognosis of this rare entity. METHOD: We retrospectively collected clinical, pathological and follow-up data of 10 cases with SCACP. RESULTS: There were 8 males and 2 females, with ages ranging from 26 to 74 years. The chest was most frequently involved. Histologically, 1 case only showed SCACP in situ, 9 cases presented with variable invasive components of adenocarcinoma and/or squamous cell carcinoma in addition to areas of in situ. Apocrine differentiation with decapitation was evident in 4 cases and mucinous metaplasia was noted in 1 case. P63 was positive in invasive squamous cell carcinoma, while CK7 was variably positive in invasive adenocarcinoma. Regional lymph node metastasis was confirmed by pathological examination in 4 patients. Follow up was available for 9 patients, ranging from 3 to 112 months. Three patients died of the disease within 1 year after recurrences. CONCLUSIONS: Because of high rates of regional lymph node metastasis and mortality in our patients, clinical behavior of SCACP seems to be more aggressive than that previously reported.

Spiradenocarcinoma, cylindrocarcinoma and spiradenocylindrocarcinoma: a clinicopathological study of nine cases.

AIMS: To elucidate diagnostic criteria for spiradenocarcinoma, cylindrocarcinoma and spiradenocylindrocarcinoma, and to emphasize correlations between clinical behaviour and variable morphological patterns. METHODS AND RESULTS: We investigated the clinicopathological and immunophenotypic features of nine cases. There were five men and four women, with ages ranging from 58 years to 82 years. The tumour size varied from 10 mm to 50 mm. The head and neck were most commonly involved. Three cases of spiradenocarcinoma and three cases of cylindrocarcinoma showed a salivary gland-type basal cell adenocarcinoma-like pattern, low-grade (BCAC-LG) and/or high grade (BCAC-HG). The remaining three cases of spiradenocarcinoma showed adenocarcinoma in situ, with invasive adenocarcinoma being seen in one of these cases. PAS staining revealed loss of the PAS-positive hyaline sheath in malignant zones of cylindrocarcinoma. p53 staining was variably positive in the malignant components of all cases. Follow-up was available for all patients, ranging from 5 months to 107 months. Two patients died of disease, one experienced recurrence, and one died of an unrelated cause. CONCLUSIONS: Patients with BCAC-LG have a better prognosis. BCAC-HG is more likely to be found in cylindrocarcinoma, and its clinical behaviour seems to be more aggressive. Close follow-up for early detection of recurrence and metastases is strongly recommended.

[Proliferative nodules in congenital melanocytic nevi: a clinicopathological analysis of eight cases].

OBJECTIVE: To study the clinicopathologic features, differential diagnosis and prognosis of proliferative nodules(PNs) in congenital melanocytic nevi(CMN). METHODS: Histopathologic evaluation and immunohistochemical study by EnVision method were carried out in 8 cases of PNs in CMN. The clinical information and follow-up data were analyzed. RESULTS: The age of patients ranged from 1 to 54 years (mean 27.6 years). Tumors were located on face (3 cases), on back (2 cases), upper extremities (2 cases) and lower extremities(1 case). Microscopically, PNs with expansile growth were observed in 8 cases of CMN. Melanocytes in PNs show variable pleomorphism with a mitotic activity of 0 to 4 per 10 high power fields. Blending of cells with adjacent CMN was noted in 6 cases. According to the morphology of melanocytes in PNs, it was classified into different types including large oval melanocytes (4 cases), small melanocytes (2 cases) and Spitz-nevus-like forms (2 cases). Immunohistochemically, melanocytes in PNs were consistent with those in adjacent CMN. They were diffusely positive for S-100 protein, but were either negative or focally positive for HMB45. Less than 5% of melanocytes were positive for Ki-67 in 8 cases of PN. Follow-up was available in all cases, ranging from 9 to 82 months. Seven patients with excision of single PN in CMN were alive with no evidence of disease, while 1 patient with multiple PNs in CMN was stable with disease after 62 months follow-up. CONCLUSIONS: PN is a rare melanocytic lesion arising in CMN. Recognition of its specific histologic features can help to avoid being misdiagnosed as melanoma. Long term follow-up should be recommended in patients with PNs, especially in those with atypical histologic features. Further investigation is needed to elucidate its clinical behavior.

[Cutaneous regressing/regressed malignant melanoma: a clinicopathologic analysis of 8 cases].

OBJECTIVE: To study the clinicopathologic features and differential diagnosis of cutaneous regressing/regressed melanoma. METHODS: Histopathologic evaluation and immunohistochemical study by EnVision method were performed in 8 cases of cutaneous regressing/regressed melanoma. The clinical presentation, treatment and follow-up data were analyzed. RESULTS: The age of the patients ranged from 40 to 69 years (mean 58 years). The male-to-female ratio was 3: 1. Tumors were located on the back (4 cases), sole of the foot (2 cases), ventral aspect of the toes (1 case), and the forearm (1 case). Clinically, 6 patients presented with progressive black mole of the skin, followed by subsequent focal hypopigmentation, even scarring. Two patients presented with multiple foci of dark-brown pigmentation. Microscopically, 3 cases were completely regressed malignant melanoma. Tumoral melanosis was found in 1 of 3 cases. The other 5 cases were melanoma with severe regression. The extent of regression ranged from 75% to 90%. The Breslow depth of the tumors ranged from 0.5 to 1.0 mm. Immunohistochemically, both metastatic and primary tumor cells were diffusely positive for S-100, HMB45 and Melan A, while melanophages were positive for CD68. Follow-up data were available in 8 patients, ranging from 8 to 27 months. Five patients were alive with no evidence of disease, 1 patient was alive with stable disease and 2 patients died of metastatic melanoma. CONCLUSIONS: Correlation between clinical presentation and pathologic features is important for diagnosis of cutaneous regressing/regressed melanoma. Thin melanoma with extensive regression ( ≥ 75%) should not been regarded as low metastatic risk and wide excision combined with sentinel lymph node biopsy is recommended.

A child with coexistent juvenile xanthogranuloma and Langerhans cell histiocytosis.

A 15-month-old boy was seen because of two distinct types of lesions, namely, yellowish papules on the scalp and face, and hemorrhagic macules and papules on the trunk. A biopsy specimen from one of the yellowish papules showed histopathologic and immunohistochemical changes of both juvenile xanthogranuloma and Langerhans cell histiocytosis. The section from the center of the biopsy specimen showed a proliferation of foamy histiocytes, among them Touton giant cells, which were positive for CD68, but negative for S-100 and CD1a. At the edges of the specimen was a predominantly histiocytic infiltration in the papillary dermis that was positive for S-100 and CD1a, but negative for CD68. The patient died 12 days after hospital admission consequent to disseminated intravascular coagulopathy. We did not biopsy the hemorrhagic lesions; however, this combination of findings suggests a possible relationship between juvenile xanthogranuloma and Langerhans cell histiocytosis, as previously reported.

[Cutaneous anaplastic large cell lymphoma: clinicopathologic, immunohistochemical and prognostic study of 44 cases].

OBJECTIVE: To study the clinicopathologic features, immunophenotype and prognosis of primary cutaneous anaplastic large cell lymphoma (CALCL). METHODS: Histopathologic evaluation and immunohistochemical study by Envision method were carried out in 44 archival cases of CALCL. The clinical information and follow-up data were analyzed. RESULTS: The patients presented with skin nodules, masses or plaques, sometimes associated with ulceration. The commonest sites of involvement were the extremities. Follow-up data were available in 39 patients. The overall survival rate was 87.2% (34/39). Disease relapses were detected in 46.2% (18/39) of the patients. Statistical analysis indicated that patients older than 50 years of age or with no less than two involved anatomic sites were more likely to have disease relapses (P < 0.05). Histologically, 31 cases were classified as common variant, 6 cases as small cell variant and 7 cases as neutrophil/eosinophil-rich variant. Immunohistochemical study showed that the rates of expression of CD30, CD45, CD45RO, CD43, CD3, cytotoxic protein and epithelial membrane antigen were 100% (44/44), 91.2% (31/34), 82.6% (19/23), 94.7% (18/19), 70.0% (28/40), 73.3% (22/30) and 31.8% (7/22), respectively. The CD4(+)/CD8(-), CD4(-)/CD8(+) and CD4(-)/CD8(-) immunophenotypes were found in 58.3% (21/36), 22.2% (8/36) and 19.4% (7/36) of the CALCL cases, respectively. Only one case (3.7%) expressed CD56. CONCLUSIONS: CALCL is a form of low-grade primary cutaneous T-cell lymphoma with a wide spectrum of clinicopathologic pattern. Special variants of CALCL should not be confused with other types of cutaneous lymphomas and inflammatory lesions. CALCL patients older than 50 years of age or with no less than two involved anatomic sites are more likely to have disease relapses.

Neutrophil/eosinophil-rich type of primary cutaneous anaplastic large cell lymphoma: a clinicopathological, immunophenotypic and molecular study of nine cases.

AIMS: To elucidate the clinicopathological, immunophenotypic and molecular features of neutrophil/eosinophil-rich primary cutaneous anaplastic large cell lymphoma (CALCL), and to emphasize the cutaneous manifestations, differential diagnosis and prognosis of this peculiar entity. METHODS AND RESULTS: We described the clinical presentations, histopathology, immunophenotype, molecular features and follow-up courses of nine neutrophil/eosinophil-rich CALCL cases. Various clinical lesions including multiple nodules, plaques and solitary exophytic masses with or without ulceration or crusting were noted in nine patients. Two patients died of disease progression, with one developing multiple lymph node involvement. Histologically, cohesive sheets or small clusters of neoplastic cells were admixed with large numbers of neutrophils and/or eosinophils, representing 10-40% of cells per high-power field. All nine cases showed T-cell phenotypes. The frequency of rearranged TCRB, TCRG and TCRD genes in six cases with available paraffin-embedded tissue was 100%, 83% and 33%, respectively. CONCLUSIONS: Neutrophil/eosinophil-rich CALCL should be differentiated from various infectious and non-infectious diseases, especially from non-neoplastic cutaneous CD30+ infiltrates rich in neutrophils and eosinophils. Precise correlation of clinical presentation, morphological features, phenotypic and molecular analysis can help to establish the correct diagnosis. Whether this rare variant has a significantly different prognosis from classical CALCL needs further investigation.

Intravascular large B-cell lymphoma with cutaneous manifestations: a clinicopathologic, immunophenotypic and molecular study of three cases.

BACKGROUND: Intravascular large B-cell lymphoma (IVLBCL) is an extremely rare type of malignant lymphoma characterized by exclusive or predominant growth of neoplastic cells within the lumen of blood vessels. Cases in the literature predominantly involve the skin and central nervous system, with special emphasis on the 'cutaneous variant'. METHODS: Three cases of IVLBCL with cutaneous manifestations, including two systemic IVLBCL and one cutaneous variant, were described in this study. In all cases, clinical presentation and follow-up data were meticulously evaluated and immunophenotypic and molecular studies were performed. RESULTS: All three cases displayed the B-cell phenotype and showed monoclonality with immunoglobulin heavy chain gene rearrangement. Bcl2 was expressed in the two systemic IVLBCL cases with fatal outcomes. The third patient with the 'cutaneous variant' achieved complete remission and a longer survival time of 15 months after chemotherapy. CONCLUSIONS: Skin manifestations and neurological findings, although to different degrees, are important clues to the diagnosis of IVLBCL. As most IVLBCL are grouped into the post-germinal center B-cell subtype of diffuse large B-cell lymphoma, Bcl2 expression may be correlated with a worse prognosis in IVLBCL. The cutaneous variant of IVLBCL has a significantly better outcome than that of systemic IVLBCL.

Prognostic factors in primary anorectal melanoma: a clinicopathological study of 60 cases in China.

To investigate the clinicopathological features and prognostic factors of primary anorectal melanoma, we described the clinical presentations, histopathology, and prognosis of 60 cases in China. Patients' age ranged from 17 to 86 years, with a female-to-male ratio of 2.33:1. The prevalent anatomic site of tumor was the anorectum. The mean tumor thickness was 11.5 mm, and mean tumor size was 2.9 cm. Abdominoperineal resection was performed on 38 (63.3%) patients, whereas wide local excision was performed on 22 (36.7%) patients. Thirty-three (55.0%) patients were pathologically confirmed to have lymph node metastasis, and 9 (15%) patients had clinically distant metastasis at diagnosis. Histologically, epithelioid cell (91.7%) was the predominant cell type, followed by spindle (31.7%), pleomorphic (25.0%), and small round cell (5.0%). Solid sheet, nest, pseudopapillary, and pseudoalveolar growth patterns were noted in 45 (75.0%), 22 (36.7%), 13 (21.7%), and 6 (10.0%) cases, respectively. After a median follow-up of 44 months, the 5-year disease-specific survival rate was 33.3%. Age, tumor size, depth of invasion, tumor thickness, lymphatic metastasis, and lymphovascular and perineural invasion were significantly correlated with survival in univariate analysis. Multivariate analysis revealed that age greater than 70 years and tumor invasion beyond deep muscular layer/sphincter ani externus were independent poor prognostic factors. As the largest single-institution study of anorectal melanoma in an Asian population, we concluded that anorectal melanoma is a rare and lethal malignant neoplasm with morphologic diversity. Large population-based studies are still needed to establish an efficient staging system in evaluation of prognosis and facilitation of treatment for anorectal melanoma patients.

Cutaneous rosai-dorfman disease: a clinical and histopathologic study of 25 cases in China.

Cutaneous Rosai-Dorfman disease (CRDD) is a rare proliferative disorder of histiocytes with unknown etiology, broadly different from systemic Rosai-Dorfman disease. We present the largest series of CRDD, describing the clinical manifestation, histopathology, immunohistochemistry, and follow-up course of 25 cases in China. Clinically, 39 skin lesions in 25 patients were divided into 3 main types: papulonodular type (79.5%), indurated plaque type (12.8%), and tumor type (7.7%). Extremities were the most frequently involved, followed by trunk and face. None of the patients was found to have visceral organ involvement or lymphadenopathy. Microscopically, CRDD was characterized by scattering, clusters or sheets of large polygonal histiocytes intermingled with a florid, mixed inflammatory infiltrate. The most important feature was emperipolesis, which can be highlighted by S-100 protein stain. Patch and bandlike infiltrate of numerous mature plasma cells around glands and vessels was a constant finding in all lesions. Neutrophils existed in all cases to a variable degree with 2 cases forming microabscess. Four cases were remarkable for fibrosis, and xanthomatous change was observed in 2 cases. Coexistence of localized Langerhans cell histiocytosis and CRDD was interestingly found in case 7, which was evidenced by CD1a stain. Clinical follow-up in 22 patients, ranging from 2 to 55 months, indicated that surgical excision was the exclusive effective treatment for CRDD. Partial or complete spontaneous remission was achieved in 7 patients within 6 to 55 months. Owing to its favorable outcome, CRDD should be differentiated from a variety of benign and malignant lesions. Recognition of its wide clinical spectrum and histologic features combined with S-100 protein stain can help to establish the correct diagnosis.

Acral Melanoma in Chinese: A Clinicopathological and Prognostic Study of 142 cases.

Acral melanoma (AM), as a peculiar subgroup of melanoma, is rare in Caucasians but has higher incidence in Asians. Large series of study on AM with clinicopathological features and prognostic factors is still limited, especially in Asian population. We retrospectively collected clinical, pathological and follow-up data of 142 AM cases. All patients were Chinese, with the age ranging from 24 to 87 years (mean 62.0; median 62.0). The Breslow thickness of primary lesions ranged from 0.6 to 16.3 mm (mean 4.9; median 3.7). 85.9% of the patients had acral lentiginous histologic subtype. Plantar was the most frequently involved site, followed by heels. Statistically, duration of the lesion before diagnosis (≤2.5 years), Breslow thickness >4.0 mm (T4), high mitotic index (>15 mm(-2)), presence of vascular invasion, regional lymph node metastasis at diagnosis and pathologic stage (II/III/IV) were found to be independent prognostic factors in both univariate and multivariate analyses. The prognosis of AM in Chinese is extremely poor. Our 5- and 10-year disease-specific survival (DSS) rates were 53.3% and 27.4%, respectively. Therefore, AM in Asians represents a more biologically aggressive melanoma subtype and is thought to carry a worse prognosis when compared with other races or cutaneous melanomas in other anatomic sites.

[Cutaneous Rosai-Dorfman disease].

OBJECTIVE: To investigate the clinicopathologic feature, immunophenotype and differential diagnosis of cutaneous Rosai-Dorfman disease (CRDD). METHODS: Clinical manifestation, morphologic features and immunohistochemical staining were studied in 8 cases of CRDD. RESULTS: All 8 patients presented with multiple papules, nodules and/or coalescent patches or plaques distributing over the extremities or trunk, without lymphadenopathy or other systemic abnormalities. Microscopically, the lesions were located intradermally and/or subcutaneously. CRDD was characterized by the presence of S-100 positive histiocytic cells exhibiting emperipolesis, accompanying with infiltration of mixed inflammatory cells. Fibrosis, somewhere in vague storiform pattern due to stromal responses, with distribution of individual neutrophil microabscess was seen in cases with a long course of illness. Dilated vascular spaces in dermis containing numerous large typical histiocytes were seen in 2 cases. CONCLUSIONS: CRDD is a benign, persistent proliferative disease of histiocytes. Systemic involvement is rare, outcome favorable. It should be differentiated from other types of histiocytosis, dermatofibrosarcoma protuberans, xanthoma and lymphoproliferative disorders. Immunohistochemical staining for S-100 protein and CD68 is helpful in making a correct diagnosis.

Analysis of KIT expression and gene mutation in human acral melanoma: with a comparison between primary tumors and corresponding metastases/recurrences.

KIT mutations play an important role during the pathogenesis of melanoma. Acral melanoma, which is the most common type in China, is more likely to harbor activating KIT mutations. Currently, there are few large studies on KIT expression and mutation in acral melanoma, especially in patients with matched primary/secondary pairs. Here, we investigated KIT expression and mutation in 39 primary acral melanomas together with their corresponding secondary tumors (17 lymph node metastases, 6 local recurrences, and 3 skin metastases) and explored the relationship between KIT expression, mutation, and clinicopathologic characteristics. Cytoplasmic and membranous staining for KIT was noted in 17 cases (43.6%) of 39 primary acral melanomas. KIT expression in patients without lymph node metastases at presentation was significantly higher than those with lymph node metastases (P = .024). KIT mutations were detected in 9 (23.1%) of 39 cases of primary acral melanomas. KIT expression did not correlate with KIT mutation status. In 23 cases with primary/secondary pairs, KIT mutations were observed in 6 cases. Comparison of KIT mutations between primary and secondary tumors showed a discordance rate of 13.0% (3/23). We concluded that KIT mutations are common in acral melanoma, and patients with acral melanoma should be screened for KIT mutations. Mutation status may change during metastases/recurrences after diagnosis of primary tumors. This has important clinical implications, and its mechanism needs further investigation.