Metastasizing cellular dermatofibroma. A report of two cases

Genetic Studies on a Case of Eruptive Disseminated Spitz Nevus and Review of Other 33 Cases

ABSTRACT

Eruptive disseminated Spitz nevus is an uncommon presentation of Spitz nevi. Only a few tens of cases have been published and only 6 of them have genetic studies. We present an additional case of a 29-year-old woman with dozens of Spitz nevi which had appeared since she was aged 10 years. The nevi were located on arms, inner thighs, legs, and buttocks. Nine of them were biopsied. Four presented severe atypia. Immunohistochemistry was performed on 5 of the biopsied specimens and was negative for PRAME, ROS-1, PDL-1, pan-TRK, and ALK. Molecular studies on the largest lesion demonstrated no NTRK1, NTRK2, or NTRK3 fusions. FISH study for PTEN showed no alteration in that same lesion. Next-generation sequencing was also negative for any detectable mutations in numerous genes analyzed. In conclusion, it seems reasonable to be cautious when evaluating atypia, even if severe, in cases of eruptive disseminated Spitz nevus.

Diagnosis and differential diagnosis of dermatofibrosarcoma protuberans: Utility of high-resolution dynamic contrast-enhanced (DCE) MRI

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a kind of low-grade malignant spindle cell neoplasm, the diagnosis, and treatment, which have markedly attracted clinicians' attention for its repeated recurrence. High-resolution magnetic resonance imaging (HR-MRI) has shown unique capabilities in diagnosis of various cutaneous tumors.

MATERIALS AND METHODS

Data of 29 patients with clinically suspected DFSPs and undergoing dynamic contrast-enhanced (DCE) HR-MRI preoperatively were prospectively collected. The HR-MRI qualitative features were evaluated and compared. The DCE-associated quantitative parameters and the time-signal intensity curve (TIC) types were provided using DCE sequences.

RESULTS

A total of 7 DFSPs, nine dermatofibromas (DF, including four cases of cellular variant [CDF]), 12 keloids, and one nodular fasciitis were enrolled. DFSP showed the largest major diameter and the deepest depth. Five DFSPs (71.4%) showed ill-defined margins as well as infiltration of peripheral adipose. All DFSPs showed irregular shape. Most DFSPs presented hyperintensity on T₂ WI (71.4%) and iso-intensity on T₁ WI (85.7%). Six cases (85.7%) had significant enhancement, and six cases (85.7%) had homogeneous enhancement. There were significant differences of K^trans , K_ep , V_e and iAUC values among DFSPs, DFs, and keloids, and DFSP had the highest values for these parameters. Six DFSPs (85.7%) and four CDFs (100%) showed type-III TICs, while the other lesions showed type-Ⅰor type-Ⅱ TICs.

CONCLUSIONS

DCE-HR-MRI could show the growth characteristics of DFSPs, which was of great value for the diagnosis and differential diagnosis of DFSPs and was helpful for the determination of treatment options, thereby to improve the prognosis of patients.

Eruptive Spitz nevus, a striking example of benign metastasis

Metastasis is generally considered a characteristic of malignant tumors. Herein, we describe a patient with more than one hundred discrete Spitz nevi scattered all over her skin. Molecular analysis from three of the lesions identified a ROS1 fusion oncogene with identical genomic breakpoints, indicating that the nevi arose from a single transformed melanocyte and then disseminated throughout the integument. The demonstration of widespread distribution of a benign tumor with limited proliferative capability indicates that metastatic dissemination is not contingent on full malignant transformation. Thus, eruptive Spitz nevus is a striking example of benign metastasis, demonstrating that metastasis can occur before malignant transformation.

Perineural Invasion as a Clue to Malignant Behavior in a Dermatofibroma

Dermatofibroma (DF) represents one of the most common mesenchymal proliferations of the skin. Their recurrence rate, even when incompletely excised, is very low, whereas the atypical, aneurysmal, and cellular variants have recurrence rates of up to 20% each. Extraordinary rare malignant lesions with metastases to lymph nodes and/or lung have been described. We report a 64-year-old woman with a long history (years) of a skin lesion on her right arm that became painful during the last months. Histologically, it consisted of a conventional cellular DF in which perineural invasion was present. Subsequently, the lesion showed a clinically aggressive course with recurrences, sarcomatous transformation, and pulmonary metastases. Given that no predictive morphological features have been identified to separate classical benign DF from rare metastasizing forms, perineural invasion in an otherwise conventional DF could be a histopathologic clue for an adverse prognosis and should provoke a closer clinical follow-up.

Dermatofibroma—A Critical Evaluation

Dermatofibromas are common cutaneous lesions. In most cases, they can be readily identified clinically and show a typical histology. In a small percentage of cases they show unusual clinical and more often histologic features that may cause differential diagnostic problems. In addition there are reactive fibrous lesions with neural or smooth muscle features that we speculate may represent dermatofibroma variants.

A primary cellular fibrohistiocytoma of the lung: Report of a case

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We experienced a rare patient with a primary cellular fibrohistiocytoma (CFH).

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Our search of literature only revealed one case of a primary CFH of the lung.

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It is essential to perform resection with an adequate margin with close clinical follow-up.

Introduction

Cellular fibrohistiocytoma (CFH) is a type of fibrohistiocytic tumor that commonly occurs in the dermis and superficial subcutis. The designation is used for lesions that show increased cellularity with a fascicular growth pattern and frequent extension. Our search of literature only revealed one case of a primary CFH of the lung. We experienced a rare patient with a primary CFH of the lung.

Presentation of case

We herein present a rare case of a 77-year-old female patient without a cutaneous lesion, who underwent resection for what was considered to be a primary CFH of the lung. There has been no recurrence including a cutaneous lesion in a year after surgery.

Discussion

CFH is considered to be benign, but rare cases showing multiple recurrences and involving metastasis to the lymph nodes and internal organs have been reported. At present, it is not possible to predict this aggressive biological behavior based on the tumor histology.

Conclusion

It is essential to perform resection with an adequate margin with close clinical follow-up.

From melanocytes to melanomas

Melanomas on sun-exposed skin are heterogeneous tumours, which can be subtyped on the basis of their cumulative levels of exposure to ultraviolet (UV) radiation. A melanocytic neoplasm can also be staged by how far it has progressed, ranging from a benign neoplasm, such as a naevus, to a malignant neoplasm, such as a metastatic melanoma. Each subtype of melanoma can evolve through distinct evolutionary trajectories, passing through (or sometimes skipping over) various stages of transformation. This Review delineates several of the more common progression trajectories that occur in the patient setting and proposes models for tumour evolution that integrate genetic, histopathological, clinical and biological insights from the melanoma literature.

A Case of Cellular Fibrous Histiocytoma on the Right Elbow with Repeated Relapse within a Short Period

Cellular fibrous histiocytoma, a variant of fibrous histiocytoma, is a designation used for lesions showing increased cellularity with a fascicular growth pattern and frequent extension into the subcutis. Here we describe a case of cellular fibrous histiocytoma showing repeated recurrence in a 36-year-old woman who initially presented with a 2-cm cutaneous tumor on her right elbow. Histopathologically, the first resected specimen demonstrated irregularly arranged collagen fibers mixed with scattered proliferating plump to spindle-shaped fibrohistiocytes. However, examination of the resected specimens obtained after recurrence showed that the cellularity had increased, the spindle-shaped cells showing monomorphic proliferation with a fascicular and storiform growth pattern extending into the subcutis, as well as an increase of Ki-67 positivity. Since the lesion showed repeated relapse within a short period, we performed wide-field resection of the tumor with a 3-cm margin. Currently, 48 months after surgery, there has been no local recurrence or metastasis, but continuous strict follow-up will be necessary.

[Atypical histiocytoma in a child]

BACKGROUND

Histiocytoma (HC) is a very common benign tumour generally seen in the lower limbs of adults, particularly women. There are, however, atypical forms of HC that behave like locally aggressive tumours, occasionally with relapse or even metastasis. Herein we report a case of locally aggressive HC in a child, which, on account of its clinical extension, required seven surgical procedures to achieve complete excision.

PATIENTS AND METHODS

A 13-year-old child consulted for a hard purplish papule measuring 8 mm in diameter located in the right lumbar region. Punch biopsy revealed a poorly delineated dermal-hypodermic tumour comprising randomly distributed moderately pleomorphic fusiform cells, arranged in bands or with storiform architecture, certain of which were multi-nucleated. The mitotic index was high (11 mitoses in 10 fields at high magnification). There was no expression by the tumour of melanocytic markers (PS100, Melan-A), histiocytic markers (CD68) or CD34. FISH analysis showed the absence of COL1A1-PDGFB fusion gene. Based on these immunohistochemical and molecular findings, a diagnosis was made of atypical HC with high cellular density. Since the lower margins of the section showed tumoural foci, surgical excision was performed with 5-mm margins. Because the lateral and vertical limits were reached in all cases, a series of five further procedures (the last of was preceded by multiple peripheral biopsies) was necessary to achieve complete excision. These multiple excision procedures resulted in total excision of 25 cm across the longest side. No clinical relapse was seen after 25 months.

DISCUSSION

Cellular or atypical forms of HC carry a high likelihood of post-surgical relapse. They are characterised by marked pleomorphism and high cellular density. In our patient, the extent of the lesion had been greatly underestimated initially, resulting in the need for several surgical procedures in order to achieve complete excision. It is thus important to highlight the predictive factors for this type of tumour in order to enable sufficiently extensive excision, or excision guided by previous biopsies, to be contemplated from the outset. These predictive factors are: young patient age, unusual location (trunk, face, neck), high cellularity, marked mitotic activity and deep extension.

Dermatofibroma of the face: a clinicopathologic study of 20 cases

INTRODUCTION

Dermatofibroma is one of the most common benign skin tumors. It typically develops on the lower limbs between the third and fifth decade of life and is more common in women. Clinical diagnosis is often straightforward. Dermatofibromas are associated with a very low rate of local recurrence following excision.

OBJECTIVES

To describe the clinical and histologic features of dermatofibroma of the face based on our experience.

MATERIALS AND METHODS

Descriptive retrospective study of the clinicopathologic features of dermatofibromas of the face diagnosed at the dermatology department of Hospital General Universitario de Valencia between 1990 and 2012.

RESULTS

Twenty cases of dermatofibroma of the face (1.11% of all dermatofibromas diagnosed) were studied. The age at onset varied widely, from 28 to 84 years. The mean age at onset was 57.15 years and the median was 54 years. There were 11 women and 9 men. Mean follow-up was 83 months and there were no local recurrences. All the tumors were confined to the papillary and reticular dermis and the storiform pattern was the most common growth pattern observed.

CONCLUSIONS

This study of facial dermatofibromas diagnosed at our hospital over a period of 22 years suggests that the face is an uncommon site but that dermatofibromas in this location behave similarly to those occurring elsewhere on the body.

Metastasizing "benign" cutaneous fibrous histiocytoma: a clinicopathologic analysis of 16 cases

Cutaneous fibrous histiocytoma (FH) is considered a benign tumor; however, certain types of FH have been shown to have a tendency for local recurrence, and there are rare reported cases of metastasis. In this study, 16 cases of morphologically benign FH with locoregional or distant metastasis were identified in consult files. Pathologic features of primary, recurrent, and metastatic tumors, as well as clinical outcome, were evaluated. Nine were male and 7 were female patients; mean age was 42 years (range, 3 to 68 y). Primary tumors arose on the leg in 5 patients, buttock in 1, trunk in 3, shoulder in 3, neck in 2, and finger in 1. The primary site in 1 case was unknown. Fifteen primary tumors available for review involved the dermis; 6 extended into the superficial subcutis. Tumor size ranged from 1 to 5 cm (median 3.2 cm). Histologically, primary tumors showed characteristic features of FH, being composed in most cases of a polymorphous population of bland spindle and histiocytoid cells in a mixed storiform and fascicular growth pattern with admixed foam cells, multinucleate cells, and inflammatory cells in varying proportions. Histologic variants included 11 cellular (2 with mixed atypical and cellular features), 2 aneurysmal, 1 atypical, and 1 epithelioid type. All tumors showed entrapment of hyalinized collagen bundles. Mitotic activity ranged from <1 to 13/10 HPF. Focal necrosis was seen in 1 primary tumor. Ten patients had local tumor recurrence; 4 patients had multiple local recurrences. Time to first recurrence ranged from 6 weeks to 13 years. The local recurrences of 1 tumor showed increased cytologic atypia, but recurrences were otherwise morphologically similar to primary tumors. Metastases occurred 0 to 180 months after diagnosis (median 17 mo) and involved the lungs (12 patients), lymph nodes (8), soft tissues (6), and liver (1). Five patients developed multiple satellite nodules in the region of the primary tumor. Metastases were morphologically similar to the primary tumors. So far, 6 patients died of disease, with a median time to death of 64 months (range, 10 to 168 mo). Four patients are alive with metastatic disease. Two patients are disease free at last follow-up, and 1 patient died of unrelated disease. Metastasis of morphologically benign cutaneous FH is an extremely rare but clinically aggressive event. Primary tumors tend to be large and cellular, but aggressive behavior cannot be predicted on morphologic grounds alone; however, early or frequent local recurrence may warrant closer clinical follow-up.

Malignant dermatofibroma: clinicopathological, immunohistochemical, and molecular analysis of seven cases

Dermatofibroma (cutaneous fibrous histiocytoma) represents a common benign mesenchymal tumor, and numerous morphological variants have been described. Some variants of dermatofibroma are characterized by an increased risk of local recurrences, and there are a few reported metastasizing cases. Unfortunately, an aggressive behavior cannot be predicted reliably by morphology at the moment, and we evaluated the value of array-comparative genomic hybridization (CGH) in this setting. Seven cases of clinically aggressive dermatofibromas were identified, and pathological and molecular features were evaluated. The neoplasms occurred in four female and in three male patients (mean age was 33 years, range 2-65 years), and arose on the shoulder, buttock, temple, lateral neck, thigh, ankle, and cheek. The size of the neoplasms ranged from 1 to 9 cm (mean: 3 cm). An infiltration of the subcutis was seen in five cases. Two neoplasms were completely excised, whereas an incomplete or marginal excision was reported in the remaining cases. Local recurrences were seen in six cases (time to the first recurrence ranged from 8 months to 9 years). Metastases were noted between 3 months and 8 years after diagnosis in six patients. Two patients died of disease, and two patients are alive with disease. Histologically, the primary tumors showed features of cellular dermatofibroma (four cases), cellular/aneurysmal dermatofibroma (one case), atypical/cellular dermatofibroma (one case), and classical dermatofibroma (one case). Mitotic figures ranged from 3 to 25 per 10 high-power fields, and focal necrosis was present in five cases. Interestingly, malignant transformation from cellular dermatofibroma to an obvious spindle cell/pleomorphic sarcoma was seen in one primary and in one recurrent neoplasm. Five neoplasms showed chromosomal aberrations by array-CGH, suggesting that these changes may represent an additional diagnostic tool in the recognition of cases of dermatofibroma with a metastatic potential.

Subcutaneous dermatofibroma

Dermatofibroma (DF) is usually confined to the dermis and the overlying epidermis is usually hyperplastic. Although DF with deep subcutaneous extension is commonly encountered, purely subcutaneous DF is uncommon. In this review, we describe a case of a 41-year-old male patient who presented with a painless, subcutaneous, hard papule on the left thigh. After the skin had been incised the lesion was totally removed, and histopathology revealed a subcutaneous dermatofibroma.

[Lipoma and atypical lipomatous tumor within the same neoplasia: Evidence for a continuous transition]

The case of a lipomatous tumor with a predominant lipoma component and transition to an atypical lipomatous tumor is presented. A deep-seated soft tissue tumor of the right thigh with a maximum size of 14 cm was resected in a 70-year-old female patient. Corresponding to a comparable macroscopic aspect, the lesion revealed the histological features of an ordinary lipoma without atypia in about 80% of the specimen. In the remaining portion (approximately 20%) histopathology showed an atypical lipomatous tumor (ALT, lipoma-like subtype). Immunohistochemistry for MDM 2 and CDK4 revealed no immunoreactivity in the lipoma component, but within the ALT component. Interphase dual-color fluorescence in situ hybridization showed no amplification of the MDM 2 gene and rarely CDK4 gene amplification within the lipoma component, but high level amplification of MDM 2/CDK4 gene in the ALT area, further supporting the morphologically based diagnosis of a lipomatous tumor including areas of a true lipoma and ALT. This case underlines the concept of a continuous stepwise development of lipomatous soft tissue tumors from benign to malignant counterparts as a biological continuum.

Cystic fibrohistiocytic tumor of the lung presenting as a solitary lesion

Cystic fibrohistiocytic tumor of the lung is a rare neoplasm. In many cases it represents a metastasis from a benign or low-grade fibrohistiocytic tumor of the skin, but occasionally it may be primary. Radiologically it usually occurs as a cystic change of multiple pulmonary nodules, and pneumothorax is the most frequent presenting symptom. We present here a 16-year-old man with recurrent right pneumothorax. The patient had no history of cutaneous fibrohistiocytic lesions. He underwent videothoracoscopic right apical segmentectomy, right lower lobe nodulectomy, and pleuroabrasion. Microscopy of the apical segmentectomy showed a cystic fibrohistiocytic tumor, whereas the nodule of the lower lobe was an intraparenchymal lymph node. The patient is alive with no tumor recurrence. The differential diagnosis includes Langerhans cell histiocytosis, lymphangioleiomyomatosis, pleuropulmonary blastoma, and metastatic endometrial stromal sarcoma. This disease usually occurs with multiple pulmonary cysts and cavitation. This case is the first reported presenting as a single lesion.

Cutaneous fibrohistiocytic tumours - an update

The term 'fibrohistiocytic' tumour is a descriptive designation without histogenetic connotation for a group of heterogeneous lesions that share morphological features of histiocytes and fibroblasts on light microscopy. However, over the years it has become apparent that many so-called 'fibrohistiocytic' tumours are largely composed of relatively undifferentiated mesenchymal cells, but can also show areas of myofibroblastic differentiation. This review focuses on the clinical and histological features as well as differential diagnosis of so-called fibrohistiocytic tumours. Special emphasis is given to more recently described histological variants of fibrous histiocytoma, e.g. cellular, epithelioid, aneurysmal and atypical fibrous histiocytoma, to angiomatous and plexiform fibrous histocytoma (plexiform fibrohistiocytic tumour), lesions that are not true variants of fibrous histiocytomas but have erroneously been designated such, and to atypical fibroxanthoma. The literature on metastasizing fibrous histiocytoma is also reviewed.

Recurrence of a laryngeal spindle cell sarcoma with a transformation into a higher grade of malignancy

Primary malignant mesenchymal neoplasms of the larynx are rare. Sarcomas of the larynx account for <1% of all malignant laryngeal mesenchymal neoplasms. This report examines a case of a recurring laryngeal, initial benign-appearing mesenchymal tumour, which first changed its clinical phenotype without any histological signs of malignancy and later also its histological appearance with signs of malignancy. Finally, it even underwent a transformation into a higher grade of malignancy. In addition to this, the difficulties of allocating this tumour to the correct sarcoma subentity are shown.

Current progress of immunostains in Mohs micrographic surgery: a review

Mohs micrographic surgery is often considered the treatment of choice for a variety of skin malignancies. In recent years, the application of immunostaining techniques has facilitated the successful removal of a number of common and less common cutaneous malignancies, including basal cell carcinoma, squamous cell carcinoma, malignant melanoma, dermatofibrosarcoma protuberans, microcystic adnexal carcinoma, sebaceous carcinoma, atypical fibroxanthoma, extramammary Paget's disease, and even sarcomas. Immunostains highlight the tumor cells and allow the Mohs surgeons to pinpoint and eliminate the residual tumor at the surgical margin. It is especially helpful when a tumor presents with subtle or nonspecific histologic features or when a tumor is masked in a pocket of dense inflammation. However, the cost, the labor, and the time consumption are of concern to many of our peers, as are the diversity of antigens, which may overwhelm some. This article serves as a review of the literature on current uses of immunostaining in Mohs micrographic surgery and as a summary of their realistic applications in the dermatologic surgeon's practice. We conclude that immunohistochemical technique has played an important role in Mohs surgery advancement. With greater use and more cost-effective staining methods, we believe that the use of immunostains in a Mohs practice will become routine.

Deep "benign" fibrous histiocytoma: clinicopathologic analysis of 69 cases of a rare tumor indicating occasional metastatic potential

Benign fibrous histiocytoma (FH) is one of the most common mesenchymal neoplasms of the skin. Several histologic variants of cutaneous FH have been described, some of which also have distinct clinical features including a propensity for local recurrence. Deep benign FH is an uncommon and poorly recognized clinical subtype that arises in subcutaneous or deep soft tissue. Only a single small series of these neoplasms has been published, and their clinical behavior is not well characterized. In this study, we report the clinicopathologic features of 69 deep FH retrieved from our consultation files. The patients included 41 males and 28 females, ranging in age from 6 to 84 years (median, 37 y). The most common anatomic location was the extremities (58%); the remainder arose on the head and neck (22%), trunk (11%), and in the deep soft tissue of the retroperitoneum, mediastinum, or pelvis (9%). All lesions arising in nonvisceral soft tissue were subcutaneous. The tumors ranged from 0.5 to 25 cm in size (median, 3.0 cm) and were well circumscribed grossly and microscopically. All tumors were composed of bland ovoid to spindle cells arranged in a storiform pattern with admixed lymphocytes. Multinucleate giant cells, osteoclastic giant cells, and/or foam cells were present in 59% of cases, whereas the other 41% were cytologically monomorphic, often resembling cellular FH. Other common findings included a hemangiopericytomalike vascular pattern (42%) and stromal hyalinization (39%). Four cases were classified as atypical deep FH due to the presence of scattered markedly pleomorphic spindle cells within an otherwise histologically typical lesion. The median mitotic rate was 3/10 HPF; 10 cases (14%) had >10 mitoses/10 HPF. Necrosis (2 cases) and lymphovascular invasion (1 case) were rare. Immunohistochemistry revealed expression of CD34 in 20/50 cases (40%), smooth muscle actin in 15/40 (38%), and focal desmin in 1/12 (8%). Of the 37 patients for whom clinical follow-up was available (median, 40 mo), 8 (22%) had a local recurrence; in all 8 cases, the tumor had been marginally or incompletely excised. Metastases occurred in 2 patients (5%), both of whom ultimately died of disease; however, this number is likely exaggerated due to consultation bias. The metastasizing tumors were large (6 and 9 cm) and 1 had tumor necrosis but they were otherwise histologically identical to the nonmetastasizing lesions. In summary, deep FH has many histologic features in common with cutaneous cellular FH; however, it usually has a more diffusely storiform pattern than the latter, is well circumscribed, and may have striking hemangiopericytomalike vessels. Similar to the cellular, aneurysmal, and atypical variants of FH, deep FH recurs in approximately 20% of cases and may rarely metastasize.

Mitosis in dermatofibroma: a worrisome histopathologic sign that does not necessarily equal recurrence

BACKGROUND

High mitotic rate is a worrying histopathologic feature that pathologists occasionally face when diagnosing benign fibrous histiocytoma (BFH), that otherwise seem to be benign. The clinical significance of this histologic feature has not been completely studied, because no studies on large series of BFH have been carried out, concerning mitotic rate as the only worrisome morphologic sign, in relation with recurrence.

METHODS

In order to study how common a high mitotic rate is in BFH, which do not present any other worrisome morphological signs, we studied 200 cases from our archives and counted the number of mitosis per 10 high power fields (HPFs) in all of them. We selected those cases that had a mitotic number of 4 or more mitosis per 10 HPF. We also performed the immunohistochemical study with MIB-1 antibody (DakoCytomation, Denmark A/S). The clinical histories of the patients were also reviewed, in order to find out if there had been any recurrence.

RESULTS

Four BFH presented four or more mitosis in ten HPF. None of them had presented any recurrence or metastasis, and the follow-up time was at least for 71 months.

CONCLUSIONS

We conclude that common BFH can occasionally present a high mitotic rate and still show a benign behavior.

Metastasizing dermatofibroma in lung

Benign dermatofibroma is very common skin tumor and can very rarely metastasize. We report a case of metastasizing dermatofibroma on a 36-year-old woman who presented multiple bilateral lung nodules. She underwent incisional biopsy for cellular dermatofibroma of the right shoulder 7 years ago. Chest computed tomographic scanning shows multiple nodules in both lung fields. Segmental and wedge resections were done. Grossly, the masses were hemorrhagic cysts. Microscopically, there were dilated cystic airspaces. The airspaces were lined by respiratory and metaplastic squamous epithelium with underlying layers of fibrohistiocytic spindle cells with storiform and fascicular pattern. The tumor cells stained for CD68 and CD10. The lung mass shows same histologic features with skin lesion.

Benign fibrous histiocytoma of the eyelid mimicking keratoacanthoma

We report a case of benign fibrous histiocytoma (BFH) of the medial canthus that mimicked keratoacanthoma in clinical appearance and growth. Excisional biopsy confirmed the diagnosis of the cellular subtype of benign fibrous histiocytoma. These types of BFH are typically more aggressive in growth, with a high recurrence rate and a tendency to undergo autonomous growth at other sites. The diagnosis of BFH should also be considered among those that appear typical of keratoacanthoma. Similar to other rapidly enlarging eyelid tumors, prompt excisional biopsy is recommended.

Fibrohistiocytic skin tumors

The fibrohistiocytic tumors of the skin are a heterogeneous group of dermal/subcutaneous mesenchymal neoplasms which show fibroblastic, myofibroblastic and histiocytic (macrophage-like) differentiation, often one beside the other in the same tumor. "Fibrohistiocytic" means in this context the morphologic similarity of the cells with fibroblasts and histiocytes. The WHO classification of 2005 includes the following entities as fibrohistiocytic tumors of the skin: BENIGN: 1. Fibrous histiocytoma (FH)/(synonymous: Dermatofibroma. Variants of FH: 1a. cellular fibrous histiocytoma, 1b. atypical (pseudosarcomatous) fibrous histiocytoma, 1c. aneurysmatic fibrous histiocytoma, 1d. epithelioid fibrous histiocytoma; 2. dermatomyofibroma; 3. (juvenile) xanthogranuloma. INTERMEDIATE: 4. plexiform fibrohistiocytic tumor; 5. dermatofibrosarcoma protuberans; 6. atypical Fibroxanthoma. MALIGNANT: 7. malignant fibrous histiocytoma. All these entities are reviewed in this paper with particular attention devoted to differential diagnostic considerations.

Expression of CD163 in dermatofibroma, cellular fibrous histiocytoma, and dermatofibrosarcoma protuberans: comparison with CD68, CD34, and Factor XIIIa

BACKGROUND

Distinction between cellular fibrous histiocytomas (FHs) with a deep component and dermatofibrosarcoma protuberans (DFSPs) can pose diagnostic problems. While CD68, CD34, and Factor XIIIa are helpful in distinguishing between these entities, none are diagnostically absolute. Recent work with CD163, a hemoglobin scavenger receptor, has demonstrated that this marker has high specificity for monocytes, macrophages, and histiocytes. Our goal is to evaluate the utility of CD163 in the diagnosis of dermatofibromas (DFs), cellular FHs, and DFSPs.

METHODS

Sixty cases including 19 DFs, 23 cellular FHs with a deep component, and 18 DFSPs were tested with antibodies against CD163, CD68, CD34, and Factor XIIIa.

RESULTS

CD163 was expressed in 17/19 (89%) DFs, 23/23 (100%) cellular FHs, and 3/18 (17%) DFSPs. CD68 was positive in 8/19 (42%) DFs, 19/23 (83%) cellular FHs, and 1/16 (6%) DFSPs. CD34 was expressed in 1/19 (5%) DFs, 5/23 (22%) cellular FHs, and 100% of DFSPs. Factor XIIIa labeled 4/19 (21%) DFs, 11/23 (48%) cellular FHs, and 0/17 cases of DFSPs.

CONCLUSIONS

CD163 expression is helpful in distinguishing between cellular FHs and DFSPs and will be useful in a panel of antibodies when these entities are in the differential diagnosis. Sachdev R, Sundram U. Expression of CD163 in dermatofibroma, cellular fibrous histiocytoma, and dermatofibrosarcoma protuberans: comparison with CD68, CD34, and Factor XIIIa.

Cystic fibrohistiocytic tumours presenting in the lung: primary or metastatic disease?

AIMS

Cystic fibrohistiocytic tumour of the lung is a rare proliferative process. Its histogenesis is uncertain, but evidence suggests that some cases represent metastatic disease from apparently indolent skin lesions, namely cellular fibrous histiocytomas. This study presents four cases and reviews the literature concerning this pattern of disease and its aetiology.

METHODS AND RESULTS

All patients were male (age range 35-54 years). Two presented with recurrent haemoptysis. Two cases had histories of cutaneous fibrohistiocytic lesions in the chest wall, excised 10 and 23 years prior to presentation with lung disease. Imaging data showed multiple bilateral cystic lung lesions in all four patients with nodular cavitating opacities seen on high-resolution computed tomography scans. Microscopy showed variably dilated thin-walled cystic airspaces lined by cuboidal epithelium and an underlying layer of mildly pleomorphic spindle cells with slightly wavy morphology and storiform architecture, admixed with inflammatory cells. Tumour cells stained for CD68 in three of four cases. All cases were negative for CD34. All patients were alive with disease, although one required pneumonectomy for intractable haemoptysis.

CONCLUSION

This study and a review of published cases show that the majority of cystic fibrohistiocytic tumours of the lung probably represent metastases from cellular fibrous histiocytomas. However, rare cases may be either primary in origin or the primary site remains occult; the term cystic fibrohistiocytic tumour remains appropriate for such cases.

Benign fibrous histiocytoma with indeterminate cells and eosinophils: collision, differentiation, or involution?

This report describes the clinicopathologic, immunohistochemical, and ultrastructural features of a benign fibrous histiocytoma of 3 years' duration situated on the posterior right arm of a 17-year-old woman. To our knowledge, this is the first published description of an association between the histologic features of benign fibrous histiocytoma with proliferating dermal dendrocytes and solid clusters of indeterminate cells and inflammatory infiltrate containing numerous eosinophils. Cell type identification was confirmed by immunohistochemical demonstration of positivity of indeterminate cells for CD1a and S-100 protein, by absence of Birbeck granules in electron microscopy study, and by positivity of fibroblast-like cells for factor XIIIa and negativity for CD34. Mitosis or cytologically atypical cells were absent. The MIB1-measured proliferative index of the tumor cells was less than 5% in spindle cells and approximately 15% in indeterminate cells. Possible pathogenic pathways are discussed that could account for divergent differentiation or a combination of neoplasms of different lineages.

Atypical fibrous histiocytoma of the skin: clinicopathologic analysis of 59 cases with evidence of infrequent metastasis

Atypical fibrous histiocytoma is an uncommon, poorly documented variant of cutaneous fibrous histiocytoma. We studied 59 cases of atypical fibrous histiocytoma to better characterize the clinicopathologic spectrum. There were 33 males and 26 females (median age 38 years; range 5-79 years) with solitary lesions arising on lower (25 cases) and upper (17 cases) extremities, trunk (6 cases), head and neck (4 cases), and vulva (1 case); anatomic location was not stated in six cases. Lesions measured 0.4-8 cm in diameter (median 1.5 cm) and clinically were nodules (40 cases), polypoid tumors (18 cases), or a slightly elevated plaque (1 case). Histologically, the lesions were primarily dermal with superficial involvement of the subcutis in one third of the cases. Salient features included a proliferation of pleomorphic, plump, spindle, and/or polyhedral cells with mainly large, hyperchromatic, irregular, or bizarre nuclei, set in a background of classic features of fibrous histiocytoma, including spindle cell areas showing a storiform pattern and entrapped thickened, hyaline collagen bundles, especially at the periphery. Multinucleated giant cells, often with bizarre nuclei and foamy, sometimes hemosiderin-rich, cytoplasm were also variably present. The degree of pleomorphism varied from only focal and minimal (14 cases) or moderate (24 cases) to marked (21 cases). Mitotic activity was observed in 55 lesions, and the number of mitotic figures ranged from 1 to 15 per 10 high power fields. Atypical mitoses were noted in 20 lesions. Furthermore, some cases of atypical fibrous histiocytoma displayed other worrisome features less often observed in ordinary FH, including unusually large size (diameter >2 cm, 8 cases), involvement of the superficial subcutis (19 cases), and geographic necrosis (7 cases). Immunohistochemical studies performed in 42 cases showed only focal smooth muscle actin (10 cases) and CD34 (4 cases) positivity, whereas CD68, S-100 protein, desmin, pan-keratin, and epithelial membrane antigen were negative. Clinical follow-up data available in 21 patients (mean duration of follow-up 50.6 months, median 43 months) revealed local recurrences in three patients (one repeated); two patients developed distant metastases, one of whom died after 96 months. These two cases were not histologically distinct from the group as a whole. We conclude that atypical fibrous histiocytoma has a broader clinicopathologic spectrum than previously realized. Lesions with floridly atypical features represent potential pitfalls for overinterpretation as pleomorphic sarcoma, which would appear to be inappropriate in most cases. Provided that atypical fibrous histiocytoma is treated by complete excision, a benign outcome is to be expected in most cases. However, similar to the cellular and aneurysmal variants of fibrous histiocytoma, atypical fibrous histiocytoma shows a higher tendency to recur locally than ordinary fibrous histiocytoma and may rarely metastasize.

Testicular metastasis Of dermatofibrosarcoma protuberans: A case report - An Ultrasonography approach

Dermatofibrosarcoma protuberans (DFSP) is a highly recurrent low-grade soft tissue sarcoma, which is usually located on the trunk. In a review of the literature there were several reports of patients with dermatofibrosarcoma with histologically documented metastasis. In all of these, there was local recurrence and subsequent metastasis to local lymph nodes and heamatogenous spread to the lungs. We present a case of dermatofibrosarcoma protuberans first time reported in the literature with metastasis to the testis evaluated by Colour Doppler sonography.

Benign fibrous histiocytoma (dermatofibroma) of the face: clinicopathologic and immunohistochemical study of 34 cases associated with an aggressive clinical course

Thirty-four cases of fibrous histiocytoma (dermatofibroma) arising on the face are reported. These neoplasms occurred frequently in females (24 female, 10 male) and showed a broad age range (12 to 85 years; mean: 43.6 years, median: 41 years). The neoplasms originated on the forehead (nine cases), the cheek (eight cases), the eyebrow (four cases), the temporal region (three cases), the nose (two cases), and the ear (one case); in seven cases the location face was given only. Five of 27 cases with follow-up information (median: 5 years) recurred locally; in one case four recurrences were excised within 8 years. The majority of cases extended into the subcutis and deep soft tissue including striated muscle (50% of cases). Histologically, only the minority of cases was composed entirely of histiocytoid and spindle-shaped tumor cells arranged in a storiform growth pattern. In many cases cellular fascicles and bundles of spindle-shaped tumor cells were noted in addition to classical morphological features of fibrous histiocytoma. A moderate mitotic rate (mean: 2.97 mitoses in 10 HPFs) was observed, and in few cases increased atypia was evident. Frank tumor necrosis and/or vascular invasion were not identified. Immunohistochemical studies revealed Factor XIIIa positivity in 13 out of 17, focal CD68 positivity in 6 out of 10, and alpha-smooth muscle actin positivity in 16 out of 19 cases tested. These lesions should be distinguished from dermatofibrosarcoma protuberans, including its fibrosarcomatous variant, leiomyosarcoma, and low-grade myofibroblastic sarcoma. Cases of fibrous histiocytoma of the face have to be excised with wider margins in comparison with examples of classical fibrous histiocytoma occurring on the extremities because of diffuse infiltration, involvement of deeper structures, and an increased rate of local recurrences.

Radiation-induced malignant fibrous histiocytoma of the neck in a patient with laryngeal carcinoma

Fibrohistiocytomas are soft tissue tumors of histiocytic origin that have a variety of histological patterns. Although cases of malignant fibrous histiocytoma (MFH) of the head and neck have been reported with increasing frequency in recent years, they are considered rare. We report a case of the giant cell variant of MFH of the neck in which the patient had been given radiotherapy for T1 glottic cancer. Prognosis of MFH, the use of radiation as primary treatment, and its role in the development of secondary primary tumors in the head and neck region are reviewed. [Editorial comment: The authors stress the important relationship between prior radiation therapy and the induction of new tumors.]

Cytogenetic evidence of clonality in cutaneous benign fibrous histiocytomas: a report of the CHAMP study group

AIMS

Cutaneous benign fibrohistiocytic tumours are among the most common soft tissue lesions. Their biological nature, in particular whether they are neoplastic or reactive, has long been disputed. Some morphological subtypes can be confused with sarcoma. Since available karyotypic data in these lesions are scarce, this study was undertaken to determine whether their cytogenetic analysis might demonstrate clonality and might help in differential diagnosis.

METHODS AND RESULTS

Thirteen karyotyped benign cutaneous fibrous histiocytomas (BFH) were morphologically reassessed and classified as ordinary BFH (eight cases), cellular BFH (four cases), and one ankle-type lesion. Five cases (38%) showed clonal cytogenetic changes, although the aberrations varied and did not correlate with histological subtypes. Karyotypic aberrations were more common in cellular BFH (3/4) than in the ordinary BFH (2/8).

CONCLUSIONS

The demonstration of clonal chromosome abnormalities, in at least some cases, supports the neoplastic nature of cutaneous BFH. The karyotypic changes identified are different from those in dermatofibrosarcoma, with which cellular BFH is often confused histologically.

Metastasizing fibrous histiocytoma of the skin: a clinicopathologic and immunohistochemical analysis of three cases

The clinicopathologic and immunohistochemical features of three metastasizing fibrous histiocytomas of the skin are presented. The first patient had a 1.3-cm nodule in the right thigh, with right inguinal lymph node metastases 19 years later. The second patient, who had a 3-cm nodule excised from his left thigh and inguinal lymph node metastasis after 4 months, had a favorable outcome 14 years after local radiotherapy and chemotherapy. The third had a 2-cm nodule in his neck, which recurred 16 months later. Four months later, cervical lymph node metastases were found. The patient was alive and well 26 months after initial surgery. All three primary skin tumors involved the dermis and subcutis, appeared well-delineated but nonencapsulated, were associated with some degree of epidermal hyperplasia, and showed features of aneurysmal/atypical or cellular fibrous histiocytoma. The number of mitoses ranged from 6 to 11 per 10 high-power fields. Recurrences and metastases showed morphologic features similar to primary lesions. Tumor cells were positive, at least focally, for CD 68, Ki-M1p, and Factor XIIIa, and occasionally for smooth muscle actin. Desmin, CD 34, S-100 protein, and cytokeratin stainings were negative. Primary neoplasms, recurrences, and metastases showed a Mib-1 labeling index of 10% or less. Cellular, aneurysmal, and atypical (pseudosarcomatous) fibrous histiocytomas of the skin can metastasize, yet they often show a protracted clinical course. Risk factors for metastatic dissemination include large size, high cellularity, aneurysmal changes, marked cellular pleomorphism, high mitotic activity, tumor necrosis, and repeated local recurrences.

Biological continuum of benign, atypical, and malignant mesenchymal neoplasms - does it exist?

The characterization of specific cytogenetic and molecular abnormalities in benign and malignant soft tissue tumours has increased our understanding and knowledge of the biology of these rare neoplasms in recent years and has led to the modification of a number of traditional classification schemes. Contrary to popular belief, it is reasonable to propose that there exists a molecular, genetic, and morphological continuum of benign, atypical, and malignant mesenchymal neoplasms. The identification of characteristic molecular changes in benign lipomas, lipomas with minimal atypia, and atypical lipomatous tumours, well-differentiated liposarcomas supports the hypothesis of a stepwise process in the pathogenesis of these neoplasms. Not only are these findings important for our understanding of the biology of soft tissue tumours, but they also may increase diagnostic and prognostic accuracy.