American Journal of Dermatopathology最新文献

Background: Maculopapular cutaneous mastocytosis (MPCM) is a rare disorder characterized by a pathologic accumulation of mast cells in the skin, which may or may not be accompanied by systemic mastocytosis. Diagnosis of MPCM on skin biopsy can be challenging because the findings may be subtle. Although mast cell density in MPCM has been reported, data informing a proposed cutoff for diagnosis and diagnostic criteria are limited.

Methods: We identified adult patients diagnosed with MPCM and urticarial tissue reaction/chronic urticaria on skin biopsy and compared the mast cell and eosinophil counts per 1 mm 2 in 10 cases each of MPCM, chronic urticaria, and normal skin from routine biopsies. All slides were stained with CD117, and CD117-positive mast cells were counted per 1 mm 2 using digital microscopy. Eosinophils were counted on hematoxylin and eosin-stained slides per 1 mm 2 using digital microscopy.

Results: The median number of mast cells per 1 mm 2 was significantly higher in MPCM than in cases of urticaria and normal skin/control tissue (177.3 vs. 26.8 vs. 47.8 mast cell per mm 2 , respectively; P ≤ 0.001). The calculated "cut point" for mastocytosis versus chronic urticaria and normal skin was 66 mast cells per 1 mm 2 , whereas the value for controls versus urticaria was 37 mast cells per 1 mm 2 . Eosinophils had similar density in MPCM and urticaria, and their presence was significant in the differentiation of MPCM and urticaria from normal tissue.

Conclusions: This study adds to the literature by providing objective mast cell density data to distinguish challenging cases of cutaneous mastocytosis from urticarial reactions and normal skin. Future studies could explore the development of computer-aided estimations of cellular density with more extensive comparison with other inflammatory conditions to translate our findings more readily into clinical practice.

Abstract: Methotrexate (MTX), an antimetabolite targeting certain autoimmune conditions and various hematologic malignancies, has been associated with iatrogenic lymphoproliferative disease (LPD) primarily of B-cell lineage. Less commonly are T-cell neoplasms where primary skin involvement is considered rare. Three cases were encountered in the medical practice of one of the authors. The patients ranged in age from 38 years to 99 years (2 women and 1 man) with 2 having rheumatoid arthritis and 1 having ankylosing spondylitis. All 3 patients received MTX. The cases included subcutaneous peripheral T-cell lymphoma not otherwise specified (NOS) (1 patient), mycosis fungoides (1 patient), and a primary aggressive epidermotropic cytotoxic T-cell lymphoma (1 patient) that proved to be fatal. One patient had spontaneous regression following MTX withdrawal; she later developed a recurrence while off MTX. Two patients died, 1 of unrelated causes and 1 of lymphoma. Seven previously reported cases included subcutaneous panniculitis-like T-cell lymphoma (2 cases), primary cutaneous CD4+ LPD (2 cases), peripheral T-cell lymphoma (NOS) (1 case), anaplastic large cell lymphoma (1 case), and peripheral T-cell lymphoma localized to fat (1 case). Regression without recurrence occurred in 6 of the 7 patients with MTX withdrawal. The patients were on the MTX for an average of 4 years and had a median age of 61 years with a slight dominance of men over women. Three of the 7 cases showed Epstein-Barr encoding region (EBER) positivity while the 3 cases reported in this series were negative. MTX-associated T-cell LPD involves older patients on long-term MTX where EBER positivity is more frequent than extracutaneous MTX-associated T-cell LPD. A spectrum of classic forms of CTCL is seen with subcutaneous involvement representing a significant percentage of cases. Regression with MTX withdrawal occurs although not in every case.

Abstract: Primary vulvar carcinomas are rare and constitute a diverse group of neoplasms. These primary tumors are typically classified based on their presumed tissue of origin or histological characteristics. Among these, carcinomas of sweat gland origin are particularly significant. They closely resemble similar malignancies in nonvulvar skin, including various cutaneous adnexal-type cancers such as apocrine and eccrine adenocarcinomas. Syringomatous carcinoma of the vulva is a rare malignant sweat gland neoplasm known for its infiltrative growth and tendency for local recurrence. Typically, these malignancies manifest as nonulcerated nodules or plaques, primarily in the head and neck region. The occurrence of syringomatous carcinoma in the vulvar region is exceptionally rare. Herein, we present a unique case of a 35-year-old woman with a dark mole measuring 1.5 × 1.0 cm on the vulva. Complete excision was performed to exhibit an infiltrative haphazard proliferation of elongated ductules and tubules, displaying significant cytologic atypia characterized by irregular nuclear contours and variably prominent nucleoli. Extensive melanocytic pigment deposition and stromal fibrosis were also observed. Immunohistochemical staining demonstrated positive expression of epithelial markers, including keratins (AE1/AE3) and epithelial membrane antigen, supporting the diagnosis of syringomatous carcinoma. CK7 and carcinoembryonic antigen were negative, whereas SOX10 and pan melanin highlighted admixed, cytologically bland melanocytes within the epidermis and neoplastic nests. This case represents a highly unusual presentation of syringomatous carcinoma associated with melanocyte colonization. Due to limited data on the optimal management strategies, a multidisciplinary approach involving gynecologic oncologists, dermatopathologists, and radiation oncologists is essential for treatment decisions. Long-term follow-up is crucial, considering the potential for local recurrence and metastatic spread, emphasizing the importance of comprehensive clinical management for favorable patient outcomes of this rare malignancy.

Background: Subcutaneous Sweet Syndrome (SSS) is a rare variant of Sweet Syndrome characterized by neutrophilic infiltration of subcutaneous adipose tissue without vasculitis. The presence of vasculitis in SSS is uncommon and poses diagnostic challenges.

Case presentation: A 38-year-old female presented with a one-year history of recurrent painful erythematous nodules on her limbs and face. Physical examination revealed asymmetrical erythematous patches and tender subcutaneous nodules with central necrotic eschars on the lower limbs. Laboratory tests were unremarkable except for a mildly elevated erythrocyte sedimentation rate. Histopathological analysis showed significant neutrophilic infiltration within the adipose lobules and vascular walls, along with extravasation of red blood cells, indicating vasculitis. The patient responded promptly to systemic corticosteroids; however, symptoms recurred upon tapering, necessitating ongoing steroid therapy.

Discussion: This case underscores the rare occurrence of vasculitis in SSS, expanding the histopathological spectrum of the disease. Literature review suggests that vasculitis in SSS may result from neutrophil-mediated vascular damage rather than immune complex deposition. The recurrent symptoms upon steroid tapering highlight the therapeutic challenges in managing SSS with vasculitis.

Conclusion: Recognition of vasculitis in SSS is crucial for accurate diagnosis and effective management. Further research is warranted to elucidate the pathogenesis and develop targeted treatment strategies for SSS with vasculitis.

Abstract: Reports of sebaceous carcinoma arising from a pre-existing benign precursor are extremely sparse in the literature. We describe a case in which there was clear transition between sebaceoma and sebaceous carcinoma, with a different pattern of p53 staining in each component.

Introduction: Melanoma arising in blue nevus (BN) is usually evident on histopathology. However, there are cases in the gray zone where neither morphology nor immunostains and molecular studies are conclusive.

Case report: A 33-year-old man presented with greenish discoloration of the abdominal skin at birth. Over time, the lesion increased in size to involve the entire left half of the abdomen, extending to the back and chest wall. He noticed nodules beneath the lesion, which were enlarging. Magentic resonanace imaging showed a lesion within the left external oblique measuring 8.3 × 6 × 4 cm and smaller lesions in the adjacent muscular planes. Gross examination of the excision showed an 8 × 6.5 × 5 cm brown-black, intramuscular nodule. Histopathology showed a BN of the overlying skin extending into the subcutis. The intramuscular nodule showed infiltrative, cellular areas with nonpigmented, plump spindle cells in nests and pseudorosettes with focal necrosis. There was minimal pleomorphism and prominent eosinophilic nucleoli. Mitoses were scarce. The neoplastic cells expressed Melan A, S100, and HMB45 with a low proliferative index (<1%). The lack of atypia and mitoses, despite clinically suspicious for melanoma, lead us to perform comparative genomic hybridization, which showed an abnormality suggesting malignancy. The patient remains with localized disease 6 years after surgery and no distant metastases.

Conclusions: Cellular nodules in a plaque-like blue nevus presenting as an intramuscular mass is hitherto unreported. It is prudent to follow-up such cases like a melanoma, despite lacking overt atypia and mutations, because metastases have been reported as late as 16 years after diagnosis.

Abstract: Angiosarcoma of the penis is an exceptionally rare mesenchymal tumor, with only about 30 cases documented in the literature. Because of its rarity and the often nonspecific clinical presentation, histopathological examination plays a critical role in accurate diagnosis. Angiosarcoma of the penis typically arises in the corpus cavernosum but has also been reported in the glans and urethra, often presenting with metastases. This report details a case of epithelioid angiosarcoma of the penis in an 84-year-old man, who presented with a rapidly enlarging, violaceous nodule on the glans penis. Histopathology revealed atypical epithelioid endothelial cells with pleomorphism and mitotic activity, and immunohistochemical markers such as CD31, Erythroblast transformation-specific [ETS]-related gene, and cellular myelocytomatosis oncogene confirmed the malignant endothelial neoplasm. The differential diagnosis excluded conditions such as epithelioid hemangioendothelioma and Kaposi sarcoma. Because of the rarity, standardized treatment protocols are lacking; however, wide excision with tumor-free margins and the potential for targeted therapies based on gene amplification are considered important. The review highlights the diagnostic challenges, prognostic factors, and current therapeutic approaches, emphasizing the need for further research to develop standardized treatment protocols.

Abstract: Primary cutaneous sarcomatoid squamous cell carcinoma can show significant histologic overlap with other malignant spindle cell tumors, posing a diagnostic challenge. Even with a wide array of immunohistochemical markers, the exact line of differentiation can be a challenge to identify in some cases. The picture is further complicated by the aberrant expression of myofibroblastic markers [such as smooth muscle actin (SMA)] by these neoplasms, along with a concomitant loss of conventional epithelial markers. The histologic differential diagnoses of primary cutaneous sarcomatoid squamous cell carcinoma include desmoplastic melanoma, leiomyosarcoma, and spindle cell atypical fibroxanthoma/pleomorphic dermal sarcoma (AFX/PDS). A retrospective analysis of 16 cases of PCSSCCs with SMA expression, obtained from large academic institutions, was performed and is summarized below. The tumors were in the scalp (6 cases), arm (4 cases), leg (2 cases), face (2 cases), hand (1 case), and neck (1 case). Immunohistochemical studies were performed in all cases with the following antibodies: AE1/AE3, CAM 5.2, MNF-116, p63, p40, CK5/6, S-100, SOX10, SMA, desmin, calponin, H-caldesmon, CD10, CD68, CD163, and CD34. Histopathologically, all cases were classified as high-grade malignant poorly differentiated neoplasms. Tumors were characterized by an infiltrative neoplasm that involved the entire reticular dermis and, in 7 cases, the subcutaneous fat. Three cases were associated with a well-differentiated squamous cell component. The neoplasms were composed of atypical spindle and epithelioid cells arranged in long and intersecting fascicles. All neoplasms were positive for epithelial markers (at least 1 marker), and all cases were strongly positive for SMA. Our data emphasize the diagnostic utility of multiple epithelial markers as a first screening tool in the detection and workup of malignant cutaneous sarcomatoid neoplasms. Awareness of SMA expression in these tumors can complicate its diagnosis, and it is important to recognize this aberrant immunophenotype to facilitate definitive diagnosis and avoid misdiagnosis.

Abstract: Myositis ossificans is a benign ossifying nodule that can affect any type of tissue but is most commonly found in muscle. Occurrence in the soft tissue of the subcutis is less common and has been referred to as panniculitis ossificans. In this case report, we describe a 46-year-old woman who presented with a 1.7 × 2.0 cm lesion on the abdomen that had been present for several months, was painful, and easily irritated by clothing. Initial clinical assessment based on history and physical examination was an epidermal cyst and removal by excision was performed. Initial histologic findings showed a spindle cell proliferation in the subcutis along with bone formation. Osteoblasts were noted to be rimming the bone and giant cells were present. The spindle cells were SMA positive and partially factor XIIIa positive while S100 protein staining was negative, confirming the diagnosis of panniculitis ossificans.