Comprehensive histopathological comparison of epidermotropic/dermal metastatic melanoma and primary nodular melanoma.

Aims: Metastatic melanoma involving the epidermis and/or upper dermis may show significant histological overlap with primary cutaneous melanoma, especially the nodular subtype. Proper histopathological classification is crucial to appropriate staging and management, but is often challenging. The aim of this study was to identify helpful histopathological features for differentiating epidermotropic/dermal metastatic melanoma (EDMM) and primary nodular melanoma (PNM).

Histopathological features of molluscum contagiosum other than molluscum bodies.

Aims: Classic histopathological features of molluscum contagiosum (MC) include a crateriform, acanthotic epidermis containing intracytoplasmic molluscum bodies (MBs). In our experience, a subset of cases lack these features on initial haematoxylin and eosin-stained sections. We aimed to describe the histopathological features of MC other than those classically described.

Primary cutaneous cribriform carcinoma: report of six cases with clinicopathologic data and immunohistochemical profile.

Background: Primary cutaneous cribriform carcinoma (PCCC) is a rare and under-recognized variant of sweat gland carcinoma, characterized by anastomosing tubules and solid nests producing a sieve-like appearance.

Methods: Six cases of PCCC were clinically, histopathologically and immunophenotypically studied.

Results: All cases showed an unencapsulated, nodular dermal tumor composed of solid and cribriform nests, cords and tubules embedded within a desmoplastic stroma.

Selected inflammatory imitators of mycosis fungoides: histologic features and utility of ancillary studies.

Mycosis fungoides is the most common primary cutaneous lymphoma; however, it remains a significant diagnostic challenge, in part because of the overlap with several inflammatory dermatoses. Despite advances in immunohistochemistry and molecular diagnostics, false-positive, false-negative, and indeterminate diagnoses are not uncommon. In most cases, the overall balance of morphologic, immunophenotypic, and genetic features must be considered carefully because there are few sensitive and specific clues to the diagnosis.

Expression of the p40 isoform of p63 has high specificity for cutaneous sarcomatoid squamous cell carcinoma.

Cutaneous spindle cell malignancies such as sarcomatoid squamous cell carcinoma (SCC), leiomyosarcoma, desmoplastic melanoma (DM) and atypical fibroxanthoma (AFX) may be morphologically indistinguishable, yet accurate diagnosis is important for appropriate clinical management. The distinction among these entities relies on immunohistochemical evaluation for epidermal, muscle or melanocytic differentiation. Epidermal differentiation markers include cytokeratins and p63.

Atypical umbilical naevi: histopathological analysis of 20 cases.

Aims: Melanocytic naevi on the umbilicus have been described as a form of flexural naevi, with the most common feature being a 'nested and dyshesive pattern'. We have encountered a distinct group of umbilical naevi with more significant atypia and prominent fibrosis, not reported previously. This study aimed to characterize these naevi more clearly.

Re-excision rates of invasive ductal carcinoma with lobular features compared with invasive ductal carcinomas and invasive lobular carcinomas of the breast.

Background: Invasive ductal carcinoma (IDC) with lobular features (IDC-L) is not recognized as a subtype of breast cancer. We previously showed that IDC-L may be a variant of IDC with clinicopathological characteristics more similar to invasive lobular carcinoma (ILC). We sought to determine the re-excision rates of IDC-L compared with ILC and IDC, and the feasibility of diagnosing IDC-L on core biopsies.

Classic versus type II enteropathy-associated T-cell lymphoma: diagnostic considerations.

Enteropathy-associated T-cell lymphoma is a rare type of peripheral T-cell lymphoma that characteristically involves the jejunum or ileum. Awareness of the histologic and immunophenotypic features of this subtype of lymphoma is important for accurate subclassification. Enteropathy-associated T-cell lymphoma has 2 forms, classic and type II, with different clinical and pathologic features.

Lupus profundus (panniculitis): a potential mimic of subcutaneous panniculitis-like T-cell lymphoma.

Lupus profundus is a rare manifestation of cutaneous lupus erythematosus, seen in 1% to 3% of patients. It most commonly presents in association with classic chronic cutaneous lesions of discoid lupus erythematosus; however, such lesions, as well as a clinical history of lupus erythematosus, may be lacking. The differential diagnosis for lymphocytic lobular panniculitides is broad; however, the consideration of subcutaneous panniculitis-like T-cell lymphoma is most critical.

Cutaneous hypertrophic lupus erythematosus: a challenging histopathologic diagnosis in the absence of clinical information.

Hypertrophic lupus erythematosus (HLE) is rare variant of chronic cutaneous lupus characterized histologically by irregular epidermal hyperplasia associated with features of classic chronic cutaneous lupus, including interface changes. Lesions frequently demonstrate reactive squamous atypia of the basal layer and may show histopathologic overlap with other more common cutaneous atypical squamoproliferative lesions. Typical histologic features of cutaneous lupus, such as follicular plugging, angiocentric lymphocytic inflammation, and dermal mucin, are very helpful clues to the diagnosis of hypertrophic lupus erythematosus.

Rosette-like structures in the spectrum of spitzoid tumors.

Background: Spitz nevi demonstrate a diverse spectrum of morphologies. Recently, there have been two reported examples of Spitz nevi with rosette-like structures similar to Homer-Wright rosettes. Rosettes have also been described in melanomas and in a proliferative nodule arising in a congenital nevus.

Invasive ductal carcinoma with lobular features: a comparison study to invasive ductal and invasive lobular carcinomas of the breast.

Invasive ductal carcinoma with lobular features (IDC-L) is not recognized as a distinct subtype of breast cancer, and its clinicopathologic features and outcomes are unknown. In this retrospective study, we focused on characterization of clinicopathologic features and outcomes of IDC-L and compared them to invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC). 183 cases of IDC-L from 1996 to 2011 were compared with 1,499 cases of IDC and 375 cases of ILC.