Not a Cyst: When a Cyst Obscures a More Nefarious Process

ABSTRACT

Angiosarcoma is an aggressive, malignant endothelial cell tumor of vascular or lymphatic origin, often arising on the head or neck of sun-damaged elderly patients. We present two cases in which the diagnosis of angiosarcoma was nearly obscured by the presence of an associated ruptured cyst or follicle. These cases serve as a reminder of the importance of careful and thorough evaluation of slides for additional diagnoses. It is important to remember that there can be more than one diagnosis in a biopsy to avoid the pitfall of missing a subtle background malignancy such as angiosarcoma.

Numerous multinucleated giant cells in cutaneous epithelioid angiosarcoma and pulmonary metastasis: A unique observation with potential diagnostic pitfalls

The histopathologic diagnosis of poorly differentiated cutaneous angiosarcoma can be challenging. We report a case of cutaneous epithelioid angiosarcoma with numerous multinucleated giant cells (MGCs) developing pulmonary metastasis. A 79-year-old man presented with a red-purple plaque on the scalp. A skin biopsy revealed epithelioid cell proliferation, admixed with numerous MGCs, and background hemorrhage. Vascular spaces were focally present and lined by atypical endothelial cells, including MGCs. Immunohistochemically, tumor cells, including MGCs, were positive for CD31, D2-40, and ERG. The patient received radiation therapy and chemotherapy, after which a follow-up CT scan revealed symptomless pneumothorax and pulmonary metastases. The patient received palliative partial lung resection, and the specimen revealed histopathological and immunohistochemical features similar to the primary cutaneous lesion. Our report expands the morphologic spectrum of cutaneous epithelioid angiosarcoma. Cutaneous angiosarcoma is an aggressive neoplasm; thus, awareness of this rare manifestation is important.

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Molecular Diagnostics of Vascular Tumors of the Skin

In this article, the authors have reviewed all the recent news regarding how the discovery of some novel and recurrent molecular and genetic changes has modified the classification of some entities and have addressed to the description of new variants of vascular tumors. And even more important, the authors also reviewed on how these findings, in addition to gain insight into the tumoral biology, portend significant clinical consequences not only regarding to their diagnosis but also to their management and prognosis because some of these mutations are potential targets for treatment. The authors have also highlighted immunohistochemical markers can help us as a surrogate marker of those molecular alterations.

Three additional cases of non-neural granular cell tumor with novel immunohistochemical findings

BACKGROUND

Non-neural granular cell tumor (NNGCT) is an uncommon neoplasm of controversial histogenesis and its histopathologic differential diagnosis includes, in addition to conventional GCT, other dermal tumors that may exhibit granular cell change.

METHODS

Three patients with a diagnosis of NNGCT were identified in the authors' files. Hematoxylin and eosin-stained sections and immunohistochemical studies were performed.

RESULTS

Histopathological study of the three lesions showed dermal proliferation of granular cells arranged in thick fascicles between collagen bundles. The lesions showed positivity for Factor XIIIa, CD163, CD68, NKIC3, vimentin, ALK, fascin, and cyclin D1.

CONCLUSION

To our knowledge, positivity for cyclin D1 has not been reported to date in NNGCT. In borderline cases, where the diagnosis is unclear despite histopathologic and immunohistochemical findings, positivity for cyclin D1 may favor the diagnosis of NNGCT. Further investigations to assess the differentiation of this rare neoplasm are needed.

Granular cell differentiation: A review of the published work

Since the initial description of the granular cell tumor in 1926, numerous other neoplasms, both benign and malignant, have been described to exhibit granular cell change. In most cases, diagnosis remains straightforward via recognition of retained histopathological morphology of the archetypal tumor, despite the presence of focal granular appearance. However, tumors with granular cell differentiation can present a diagnostic challenge either by mimicking alternative diagnoses, or by failing to exhibit architectural clues of the primary entity, thus requiring an immunohistochemical work-up. In light of this, it is important to be aware of the various entities that have been reported to exhibit granular cell morphology. In this review such tumors are discussed along with pertinent clinical and histopathological features.