CD10 is expressed in cutaneous clear cell lesions of different histogenesis

A Rare Case of Cutaneous Metastasis of Renal Cell Carcinoma to the Lateral Thigh

Renal cell carcinoma (RCC) is a common cancer type in the United States, and at the time of diagnosis, many patients already have metastatic disease. RCC typically metastasizes to the lungs, liver, and bones, with few cases manifesting cutaneous metastasis. Most incidences of RCC metastases reported in the literature have been on the face and scalp. We discuss a case of a 64-year-old male patient who presented with a history of RCC and a purpuric nodule on his lateral thigh. Histopathological examination revealed vacuolated cytoplasm with areas of cytoplasmic clearing; the cells stained positively for cytokeratin AE1/AE3, CAM5.2, and PAX8. Cutaneous metastatic RCC was subsequently diagnosed. Cutaneous manifestations of RCC, particularly to the thigh, remain a rare presentation of metastatic RCC.

CD10-Positive Cutaneous PEComa: An Extremely Rare Skin Tumour

We here present the case of a 67-year-old woman with a history of a slowly progressive, polypous nodule on her left wrist. The lesion was excised, and the histological analysis revealed a clear cell tumour that was relatively sharply demarked from the surrounding tissue extending into the subcutaneous tissue. The tumour showed a characteristic trabecular pattern in which the tumour cells were arranged around numerous vessels. The neoplastic cells had a predominantly epithelioid shape, granular eosinophilic to clear cytoplasm and prominent centrally located nucleoli. The histological differential diagnosis included a metastatic clear-cell renal cell carcinoma and a primary cutaneous perivascular epithelioid cell tumour (PEComa). Immunohistochemically, the tumour cells revealed homogenous expression of HMB-45, MiTF and CD10, whereas MART-1 and S100 were negative. Antibodies against actin marked the trabecularly arranged vessels, and the neoplastic cells yielded a patchy positivity against actin and desmin. Additional immunohistochemical stains against pan-cytokeratin, CAIX, PAX-8 and EMA were negative. Based on the morphologic and immunophenotypic findings, the histological diagnosis of a CD10-positive cutaneous PEComa was made.

Plexiform Xanthomatous Tumor, Variety of Xanthoma or Subtype of Fibrohistiocytic Tumors?

Plexiform xanthomatous tumor was proposed as an independent neoplasm within fibrohistiocytic tumor group a few years ago. The arguments were based on their different clinical features as well as their own morphological and immunohistochemical findings. Nevertheless, it has not been widely studied yet, and there are few reports about this entity. Regarding a case, we reviewed the diagnostic characteristics of this underdiagnosed tumor.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

Cutaneous metastatic breast carcinoma with clear cell features

Breast carcinoma remains one of the most common sources of skin metastases in women. Cutaneous breast carcinoma metastases have variable clinical and histopathologic presentations that can make diagnosis challenging. We report a unique case of metastatic breast carcinoma with prominent clear cell features, thus mimicking a xanthomatous process. Dermatopathologists should be aware of this entity given its resemblance to other clear cell infiltrates and neoplasms.

PAX2 and PAX8 Expression in Primary and Metastatic Renal Tumors: A Comprehensive Comparison

Context.—The diagnosis of renal cell carcinoma (RCC) remains problematic, especially in the context of metastasis or small-needle biopsies. PAX2 and PAX8 transcription factors are known to be expressed by several histologic types of renal neoplasms.

Objective.—To evaluate the diagnostic utility of PAX2 and PAX8 relative to one another, which has not been studied.

Design.—Consecutive tissue sections from the archival samples of 243 primary and 99 metastatic renal neoplasms were submitted to PAX2 and PAX8 immunostain.

Results.—Within the primary neoplasms, PAX2 versus PAX8 expression was noted in 90 of 95 (95%) versus 92 of 95 (97%) for clear cell RCC, 29 of 38 (76%) versus 38 of 38 (100%) for papillary RCC, 14 of 25 (56%) versus 22 of 25 (88%) for chromophobe RCC, 3 of 7 (43%) versus 5 of 7 (71%) for collecting duct RCC, 6 of 8 (75%) versus 8 of 8 (100%) for acquired cystic kidney disease–related RCC, and 7 of 13 (54%) versus 11 of 13 (85%) for oncocytoma. Regardless of histologic subtype, PAX8 staining was noted in more cells and with more intense staining than PAX2. Within the metastatic RCCs, PAX8 expression was more frequently positive than PAX2 expression (88 of 99 cases; 89%; versus 75 of 99 cases; 76%).

Conclusions.—Both PAX2 and PAX8 are diagnostically useful markers for both primary and metastatic renal neoplasms of a large variety of histologic types. However, PAX8 appears to be more sensitive than PAX2 in both primary and metastatic settings. PAX8 can be included in any immunohistochemical panel for the diagnosis of primary renal neoplasms. Adding PAX2 should be optional, but this would gain limited further diagnostic yield. In a metastatic setting, both PAX8 and PAX2 can be included in a panel because a small subset of metastatic RCCs are stained only with PAX2.

The use of immunohistochemistry in the diagnosis of metastatic clear cell renal cell carcinoma: a review of PAX-8, PAX-2, hKIM-1, RCCma, and CD10

The diagnosis of metastatic clear cell renal cell carcinoma may be difficult in some cases, particularly in the small image-guided biopsies that are becoming more common. As targeted therapies for renal cell carcinoma are now standard treatment, the recognition and diagnosis of renal cell carcinoma has become even more critical. Many adjunctive immunohistochemical markers of renal epithelial lineage such as CD10 and RCCma have been proposed as aids in the diagnosis of metastatic renal cell carcinoma, but low specificities often limit their utility. More recently described markers (PAX-2, PAX-8, human kidney injury molecule-1, hepatocyte nuclear factor-1-β, and carbonic anhydrase-IX) offer the potential for greater sensitivity and specificity in this diagnostic setting; however, knowledge of their expected staining in other neoplasms and tissues is critical for appropriate use. In this review, we discuss the most widely used immunohistochemical markers of renal lineage with an emphasis on their sensitivity and specificity for metastatic clear cell renal cell carcinoma. Subsequently, we present a variety of organ-specific differential diagnostic scenarios in which metastatic clear cell renal cell carcinoma might be considered and we propose immunopanels for use in each situation.

CD10 Is Expressed in Most Epithelioid Hemangioendotheliomas: A Potential Diagnostic Pitfall

Context.—Epithelioid hemangioendothelioma (EHE) is a vascular neoplasm that occasionally is difficult to distinguish from primary/metastatic carcinomas, particularly when EHEs express keratins. We recently encountered an EHE with strong CD10 positivity mimicking renal cell carcinoma.

Objective.—To examine sensitivity and specificity of CD10 in EHE.

Design.—Nine EHEs were stained with keratins, factor VIII, CD31, CD34, and CD10. Mimics of EHE were also retrieved and stained with CD10.

Results.—The EHE patients included 5 men and 4 women. Patients ranged in age from 24 to 74 years. Tumors were located in liver (3), skin (2), lung/pleura (2), and sternomastoid and mediastinum (1 each). Two had skin metastases. All EHEs were positive for vascular markers. A total of 7 of 9 primary tumors expressed cytoplasmic and intracytoplasmic luminal CD10. The 2 skin metastases were positive, whereas 2 primary skin EHEs were negative. Of the mimics, CD10 showed staining in 7 of 23 cases: 3 of 3 renal cell carcinomas, 1 of 7 other carcinomas, 2 of 3 epithelioid angiosarcomas, 1 of 3 melanomas, 0 of 3 mesotheliomas, and 0 of 4 epithelioid hemangiomas.

Conclusions.—CD10 has a sensitivity of 78% (confidence interval, 63.6%–92.4%) and specificity of 70% (confidence interval, 54%–85.9%) for EHE. There is a growing list of tumors that show expression of CD10. Pathologists should be aware of this diagnostic pitfall.

Update on immunohistochemical methods relevant to dermatopathology

CONTEXT

Dermatopathology covers a large variety of entities, some having very similar histologic appearances. Immunohistochemistry is an incredibly helpful tool that is useful in diagnosis as well as prognosis of selected skin tumors.

OBJECTIVE

To provide a comprehensive review of recent trends and immunohistochemical stains used by dermatopathologists. Emphasis is placed on new stains as well as novel uses of existing stains.

DATA SOURCES

All data were gathered from published journal articles available through the National Center for Biotechnology Information PubMed database.

CONCLUSIONS

New immunohistochemical targets are continually being found, contributing to more accurate diagnosis and classification of skin tumors. The presence of specific markers can be used to determine the aggressiveness of malignancies and design treatment strategies. In addition, application of existing stains can help determine intravascular spread of malignancy in primary cutaneous lesions. And use of rapid immunohistochemical staining techniques on frozen sections can assist in more complete excision of tumor margins. Immunohistochemistry is a highly versatile and growing tool of dermatopathologists.

CD10 and CD34 in fetal and adult human hair follicles: dynamic changes in their immunohistochemical expression during embryogenesis and hair cycling

BACKGROUND

CD10 and CD34 have been detected in both epithelial and mesenchymal components of anagen human hair follicles.

OBJECTIVES

To analyse the expression of CD10 and CD34 in human hair follicle development as well as in different phases of the hair cycle.

METHODS

Fetal and adult hair follicles at different stages of the hair cycle were examined by immunohistochemistry for CD10 and CD34.

RESULTS

In fetal follicles, CD10 is expressed by the cells of the placodes, and CD34 by the mesenchymal cells of the dermal condensate. As the follicle matures, CD10 can be seen in the matrix cells, inner root sheath and dermal sheath. In adult follicles, the expression of CD10 in the follicular epithelium is present in anagen follicles, but tends to disappear in catagen, and is not detected in telogen. The CD10 positivity of the dermal sheath is more intense in catagen than in anagen follicles. CD34 immunostaining of the external root sheath was seen in adult anagen follicles but not in fetal follicles. This staining of the anagen outer sheath tends to disappear in catagen and is not detected in telogen.

CONCLUSIONS

CD10 and CD34 are not proteins constantly present in a specific cell type of the hair follicle, but are proteins that can be expressed by both epithelial and mesenchymal cells depending on the stage of development and hair cycle. The distribution of the immunoreactivity to CD10 in the placode and CD34 in the dermal condensate suggests a role of these proteins in initial stages of hair formation.

Renal cell carcinoma marker (RCC-Ma) is specific for cutaneous metastasis of renal cell carcinoma

BACKGROUND

Renal cell carcinoma marker (RCC-Ma) is a monoclonal antibody against a normal renal proximal tubule antigen. RCC-Ma expression is relatively specific for primary clear cell renal cell carcinoma. Its expression in cutaneous metastasis of renal cell carcinoma (MRCC) and other cutaneous clear cell lesions has not been studied.

METHODS

One hundred and thirty-seven cutaneous clear cell lesions including eight xanthomas, 32 xanthelasmas, 25 xanthogranulomas, seven balloon cell nevi, six clear cell hidradenomas, 29 sebaceous adenomas, six sebaceous epitheliomas, eight sebaceous carcinomas, and 16 MRCC were examined using immunohistochemistry for the expression of RCC-Ma.

RESULTS

RCC-Ma was expressed in 10 of 16 (62.5%) MRCC, all with greater than 20% of cell labeling. Of these, 4 of 10 (40%) labeled with a membranous pattern and 6 of 10 (60%) labeled with both a membranous and a cytoplasmic pattern. RCC expression was not seen in any of the other clear cell lesions (p < 0.001). Furthermore, lack of expression in each of the other diagnostic groups was significant when each group was compared with the MRCCs (p < 0.01 at least for each group).

CONCLUSIONS

Our study demonstrates that RCC may be a valuable component of a panel of immunohistochemical markers when evaluating cutaneous clear cell lesions.

Cutaneous Balloon Cell Dermatofibroma (Fibrous Histiocytoma)

Dermatofibroma (DF) or cutaneous fibrous histiocytoma is a common benign skin tumor that exhibits multiple, distinct histologic variants. Although clear cell DF has been described in the literature, balloon cell degeneration causing a clear cell DF phenotype has been not been reported to date. Herein, we describe the clinicopathologic findings of balloon cell DF arising on the heel of a 43-year-old man. Clinically, it presented as enlarging tan-white, ulcerated, firm 1.5 cm nodule, clinically suspected to be pyogenic granuloma. Excisional biopsy revealed a circumscribed fibrous tumor populated by mostly clear and spindle cells. A zonal arrangement separated the varied tumor cells where the most superficial, polypoid area showed large, clear polygonal balloon cells; the mid-dermal zone demonstrated a transition between balloon cells, epithelioid cells, and spindle cells; and the deep dermal zone had storiform arrangement of spindle cells, with the fascicles separated by coarse collagen bundles. A CD10+ > CD68+ > Factor XIIIa+ immunophenotype was identified with negative immunolabeling for S-100 protein, HMB-45, cytokeratin AE1/AE3, desmin, smooth muscle actin, lysozyme, and leukocyte common antigen (LCA). Ultrastructurally, the clear tumor cells were filled with multiple, empty, nonmembrane bound vacuoles of varying size. No recurrence has been described after complete excision and 7 months of follow up. DF with balloon cell change, likely secondary to persistent irritation, should be added to the differential diagnosis of cutaneous primary and metastatic neoplasms showing balloon cell degeneration such as balloon cell melanocytic nevi and renal cell carcinoma, respectively.

CD10 Expression in Cutaneous Adnexal Neoplasms and a Potential Role for Differentiating Cutaneous Metastatic Renal Cell Carcinoma

Context.—Recent investigations have demonstrated the utility of CD10 as a marker for renal cell carcinoma (RCC). Cutaneous metastases occur in up to 11% of patients with RCC and may be the presenting sign of widespread disease. The differential diagnosis in histopathologic evaluation of these cases includes cutaneous adnexal neoplasms, and describing the expression of CD10 in these tumors may be helpful in delineating the differential diagnosis.

Objective.—To determine CD10 expression in a variety of adnexal lesions and to determine the diagnostic utility of CD10 in an immunohistochemical panel differentiating metastatic cutaneous renal cell carcinoma from cutaneous adnexal neoplasms.

Design.—We studied 57 primary adnexal neoplasms of eccrine (n = 31), apocrine (n = 16), and sebaceous (n = 10) differentiation as well as normal skin (n = 3) and RCC metastatic to the skin (n = 4). A CD10 monoclonal antibody was applied to formalin-fixed, paraffin-embedded tissue. Specimens were randomized and categorized as immunopositive or immunonegative by a pathologist with expertise in immunohistochemistry who was blinded to the diagnoses.

Results.—Two (6.5%) of 31 eccrine, 1 (6%) of 16 apocrine, and 4 (40%) of 10 sebaceous neoplasms demonstrated CD10 immunopositivity. Four (100%) of 4 RCC were CD10 immunopositive. CD10 expression was significant for eccrine and apocrine neoplasms (P &lt; .001) compared to metastatic RCC, but not for sebaceous neoplasms (P = .08).

Conclusion.—Based on these results, CD10 is a useful additional immunostain for the discrimination of RCC metastatic to the skin and cutaneous adnexal neoplasms with eccrine and apocrine differentiation, but not with sebaceous differentiation.

Malignant mullerian mixed tumor (carcinosarcoma) of the fallopian tube: an immunohistochemical study of neoplastic cells. Case report

The patient was a 65-year-old woman who complained of lower abdominal pain. Salpingo-oophorectomy and hysterectomy were performed due to suspicion of ovarian cancer. At surgery a polypoid mass was observed in the fimbria of the left fallopian tube. Histologically, proliferation of undifferentiated neoplastic cells with marked cytological atypia predominated in the tumor. Proliferation of rhabdomyoblastic cells or spindle cells, as well as adenocarcinoma arising from the mucosa of the fallopian tube, was observed. A diagnosis of malignant müllerian mixed tumor (MMMT) was made. CD10 was expressed in adenocarcinoma, undifferentiated, spindle and rhabdomyoblastic cells. Furthermore, rhabdomyoblastic cells were positive for desmin and myoglobin. Undifferentiated and spindle neoplastic cells were focally positive for ASMA and negative for h-caldesmon. Finally, our preliminary report suggests that MMMT of the fallopian tube may contain immature smooth muscle cells or cells with the myofibroblast-like immunohistochemical phenotype in the undifferentiated component.