American Journal of Dermatopathology最新文献

Abstract: Cocaine is a commonly abused illicit substance frequently administered through intranasal inhalation. Its potent vasoconstrictive effects are well recognized and can result in significant ischemic damage to the sinonasal mucosa. A known complication of chronic intranasal cocaine use is the development of cocaine-induced midline destructive lesions, often leading to perforation of the nasal septum and adjacent structures. Although the destructive sequelae of cocaine use are well documented in the literature, nasal hypertrophy has not been widely reported. In this study, we describe 2 patients with a history of intranasal cocaine use who presented with similarly pronounced nasal enlargement characterized by a porcine appearance. Histopathologic evaluation in both cases revealed features mimicking squamous cell carcinoma, highlighting the potential for diagnostic confusion in such presentations.

Abstract: The "clown nose" is a rare clinical presentation characterized by reddish-brown nodular lesions localized to the nasal tip. This distinctive sign has been associated with metastatic malignancies, genetic syndromes, and primary dermatologic conditions. We describe a rare case of metastatic eccrine porocarcinoma manifesting as a clown nose in a 54-year-old man with a history of metastatic lung squamous cell carcinoma. In addition, we performed a systematic literature review through PubMed to evaluate infiltration of the nose as a potential indicator of underlying tumor metastasis.

Abstract: Interdigitating dendritic cell sarcoma (IDCS) is a rare tumor derived from dendritic cells and has been reported in slightly more than 100 cases in literature. IDCS of the skin is an exceedingly rare presentation, noted in 8 case reports in published literature. We present a rare case of a 44-year-old man who presented with primary cutaneous IDCS on his posterior neck, who was later discovered to have biopsy-confirmed IDCS lung metastases. Secondary to this, the patient was found to have a superficial spreading melanoma on his left shoulder, consistent with the notion that cutaneous IDCS increases a patient's risk of secondary malignancies. Upon further investigation of his IDCS, bilateral lung metastases of IDCS were identified and the patient received several cycles of chemotherapy. This case contributes to the limited body of knowledge on cutaneous IDCS and its treatment modalities. The poor prognosis associated with metastatic IDCS highlights the importance for further research to identify treatment regimens that lead to better prognosis.

Abstract: BAP1-inactivated melanocytic tumor (BIMT) represents a distinct subtype of melanocytoma, with characteristic morphologic features. These lesions are associated with inactivation of the BAP1 tumor suppressor gene. Although there are frequently histologic features that might otherwise cause concern for malignancy, including enlarged cells with nuclear variability, prominent nucleoli, and a lymphocytic inflammatory infiltrate, empirical data suggest that the majority behave in a clinically benign fashion. We report 2 cases of cutaneous BIMT with a distinctive morphologic pattern of clonal expansion with p16 loss. In both cases, there was liver metastasis after complete excision, in the absence of locoregional recurrence. These rare cases highlight the possibility of a distinct pathway of malignant progression in BIMT.

Abstract: Melanoma is known to have a high prevalence of somatic mutations, leading to a wide range of clinical and histological variability. This genetic plasticity can result in the partial or total loss of typical diagnostic clinical and immunohistochemical features of melanoma. Undifferentiated melanoma (UM) and dedifferentiated melanoma (DM) pose a significant diagnostic challenge due to their histological atypia and the absence of conventional melanocytic markers, often making them indistinguishable from pleomorphic dermal sarcoma (PDS). Accurate differentiation, however, is critical as UM and DM, unlike PDS, display a higher metastatic potential. Molecular analysis plays a crucial role in accurate diagnosis, particularly through the detection of mutations such as BRAF and NRAS, which are rarely found in true sarcomas. We present 2 cases of primary cutaneous UM initially misdiagnosed as PDS and later reclassified based on molecular findings. A comprehensive review of the literature was performed of reported cases of primary cutaneous undifferentiated and DM. Timely diagnosis is vital to allow access to effective targeted therapies, such as immune checkpoint inhibitors and BRAF/MEK inhibitors, which have shown promising responses, suggesting that undifferentiated and DM respond similarly to conventional melanoma despite their atypical presentation.

Abstract: Cutaneous metastases of breast neoplasms indicate advanced disease with poor prognosis. The role of Preferentially Expressed Antigen in Melanoma (PRAME) expression in breast cancer skin metastases remains poorly understood. In this study, we investigate PRAME expression in breast carcinoma metastatic to the skin, particularly triple-negative breast cancers (TNBC). A retrospective review of breast cancer cases with skin metastasis was conducted from January 2005 to March 2023. PRAME immunostaining was performed on skin metastatic lesions and corresponding primary tumors. A comparison group of noncutaneous metastases (n = 11) was included. Thirty patients with cutaneous metastasis were identified (29 women, 1 man; mean age 63 years). The most common site of skin metastasis was chest (25 cases, 83%). Histologically, 25 cases (83%) were invasive ductal carcinoma. Eleven cases (37%) were TNBC. PRAME positivity was observed in 10 skin metastases (33%) with 70% being triple negative. Among 20 available primary samples, only 3 were PRAME positive with corresponding positive metastases. Comparison group showed minimal PRAME expression. In total, 40% of patients died, with TNBC associated with higher mortality ( P = 0.04). All PRAME-positive TNBC patients with follow-up were deceased. In conclusion, PRAME expression occurred in approximately one-third of breast cancer skin metastases, with predominance in triple-negative breast cancer. These findings warrant further investigation of PRAME's role in cutaneous metastasis and its diagnostic implications.

Abstract: Granulomatous dermatitis within tattoos is most often attributed to pigment reactions, infection, or sarcoidosis. We report 2 patients of secondary syphilis presenting as granulomatous inflammation confined to black tattoo ink, an uncommon manifestation. Both patients demonstrated histologic features of granulomatous dermatitis with plasma cells, spirochetes confirmed by special staining, and complete resolution after penicillin therapy. These patients highlight syphilis as an important consideration in the differential diagnosis of papules within a tattoo.

Abstract: Giant cellular blue nevi (CBN) are rare melanocytic proliferations that may mimic melanoma, posing diagnostic challenges. We report a case of a 22-year-old woman with a 6-cm bluish-gray mass on the left medial buttock that had been present since childhood. An incisional punch biopsy performed at an outside facility demonstrated a dermal proliferation of heavily pigmented and densely cellular spindled and epithelioid melanocytes that were negative for PRAME. Comprehensive molecular profiling showed a low tumor mutational burden and identified an activating GNAQ p.Q209L mutation with no alterations in BRAF , NRAS , or KIT . Further workup at our institution included a pelvic MRI that showed no evidence of invasion into adjacent muscle or bone; however, the lesion's size warranted complete surgical excision. Final pathology analysis demonstrated a large circumscribed neoplasm consisting of both spindled and epithelioid melanocytes with no significant pleomorphism, a low proliferative index, and BRAF and PRAME negativity, though perineural involvement was noted. In the context of the imaging and molecular study results, a diagnosis of giant cellular blue nevus was made. This case highlights a rare presentation of giant CBN and the utility of integrating next-generation sequencing with histopathologic evaluation to distinguish the latter from melanoma and support clinical decision making.

Abstract: Solar elastotic bands (Raimer's bands) represent a rare clinical variant of severe solar elastosis that often affects forearms. Solar elastotic bands and keratoelastoidosis marginalis are associated with extensive chronic sun exposure (actinic damage). Repetitive trauma is also suspected of playing a causative role. We present a case of solar elastotic band of the forearm in which cytokeratin AE1/AE3 stains reveal positive staining in the dermis. This finding supports the hypothesis that trauma plays a role. We explore and review the histologic and clinical findings of several forms of solar elastosis, suggesting that these entities share many features in common.