Granular cell atypical fibroxanthoma: case report and review of the literature

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.

Cutaneous Non-Neural Granular Cell Tumors Harbor Recurrent ALK Gene Fusions

Non-neural granular cell tumor (NNGCT; also known as primitive polypoid granular cell tumor) is a rare neoplasm composed of large ovoid cells with abundant granular cytoplasm, variable nuclear pleomorphism, and the potential for regional lymph node spread. In contrast to conventional granular cell tumor (GCT), NNGCT lacks S100 expression and can exhibit greater nuclear atypia and mitotic activity. Therefore, we investigated clinicopathologic features of 12 NNGCT, and also used next-generation sequencing to identify potential driver events in a subset of NNGCT and 6 GCT. NNGCT demonstrated mild-to-moderate nuclear pleomorphism, variable mitotic activity (0 to 10/10 high-power fields), and were S100. Genetic analysis of 5 cutaneous NNGCT revealed gene fusions involving the anaplastic lymphoma kinase gene (ALK) in 3 cases (60%). Specifically, an interstitial deletion of chromosome 2 resulting in an in-frame fusion of dyanactin 1 (DCTN1) to ALK was identified in 2 cases, and a translocation resulting in a fusion between sequestosome 1 (SQSTM1) on chromosome 5 and ALK was identified in one case. Two of 6 GCT (33%) showed gains of chromosome 7. No other molecular or chromosomal alterations were detected in NNGCT and GCT. ALK immunohistochemistry revealed weak-to-moderate positivity in 4/9 cutaneous NNCGT (44%) including all 3 tumors with ALK fusions. Three oral NNGCT lacked ALK expression. NNGCT with ALK immunostaining did not have morphologic features distinguishing them from those without ALK staining. Our results demonstrate that a subset of NNGCT harbor ALK fusions, suggest that NNGCT are molecularly diverse, and further substantiate NNGCT as distinct from GCT.

Conception and Management of a Poorly Understood Spectrum of Dermatologic Neoplasms: Atypical Fibroxanthoma, Pleomorphic Dermal Sarcoma, and Undifferentiated Pleomorphic Sarcoma

OPINION STATEMENT

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) tumors share many clinical, etiologic, and histologic features and likely represent components of a tumor spectrum. In dermatologic oncology, differentiating between AFX and PDS is pivotal as tumors with histological features consistent with PDS are more likely to behave in a clinically aggressive manner. Importantly, the term "pleomorphic dermal sarcoma" (PDS) is a more appropriate designation than "undifferentiated pleomorphic sarcoma" (UPS) for describing deeper, more aggressive, histologically high-grade cutaneous tumors that otherwise resemble AFX. Surgery remains the gold standard for treatment. In the setting of AFX, excision with the Mohs micrographic technique appears to offer superior tumor control rates while maintaining greater tissue preservation over wide local excision and should be considered first line. In the setting of PDS, optimal management is less clear given the paucity of available data. However, due to its greater propensity to recur and metastasize, extirpation with complete tumor margin control appears paramount. The roles of imaging and SLNB in management and clinical outcomes of AFX and PDS are unclear given the lack of available data. In reality, these tools are unlikely to be helpful in most cases of AFX. However, in the setting of PDS, emerging literature indicates that these tumors are inherently higher risk, and thus, imaging and SLNB may be helpful in select cases. Additionally, radiation therapy may be of adjuvant benefit for these tumors when clear surgical margins cannot be obtained. While traditional chemotherapy has been largely ineffectual, the recent discovery of key oncogenetic mutations has allowed for the identification of several potential molecular drug targets that may have a therapeutic role with future study. In the unfortunate setting of metastatic disease, a multidisciplinary approach is optimal. Further studies are needed to establish definitive conclusions regarding risk stratification and best management practices.

Congenital Granular Cell Tumor of the Arm: A Rare Presentation

Congenital granular cell tumors are uncommon benign tumors of newborns that mainly affect oral mucosa, especially the maxillary alveolar ridge. They are predominantly seen in female newborns, and cutaneous involvement is extremely rare. In this report, we present a case of congenital granular cell tumor on the arm of one of the male monozygotic twins and discuss the differential diagnosis of granular cell phenotype.

S-100 Negative Granular Cell Tumor of the Oral Cavity

Classic granular cell tumor is a mesenchymal neoplasm that commonly occurs on the skin, but is not infrequently found in the oral cavity, primarily on the dorsal tongue. Diagnosis is usually straightforward with hematoxylin and eosin stained slides. Immunohistochemical studies on classic granular cell tumor shows positive immunostaining for S-100 and vimentin, while CD68 is variably positive. We report a case of otherwise unremarkable oral granular cell tumor that was immunohistochemically negative for S-100, and positive for vimentin and CD68, and discuss the differential diagnosis. The results of the immunohistochemical studies in our case are compared with those of classic S-100 positive oral granular cell tumors, as well as cutaneous and oral S-100 negative granular cell tumors. Classic S-100 positive granular cell tumors and S-100 negative granular cell tumors of the oral cavity can only be distinguished by immunohistochemical studies; however, the necessity of this distinction is unclear, as both are benign lesions in which recurrence is unlikely.

A case of primitive non-neural granular cell tumor presenting as a single painless bleeding nodule

Primitive non-neural granular cell tumor is a rare tumor of uncertain lineage that clinically presents as a solitary painless nodule most typically on the extremity or trunk of an adult. We report the case of a 20-year-old man with a small reddish papule on the abdomen, measuring about 2 x 3 mm, surrounded by a faint erythematous halo. Dermoscopy examination shows diffuse red color and weak whitish striae. However, only histological and immunohistochemical evaluation allowed us to perform the correct diagnosis.

Clinicopathologic analysis of primary atypical fibrous xanthoma of the esophagus

AIM: To explore the clinical and pathological features of primary atypical fibrous xanthoma of the esophagus, and to analyze its diagnosis, treatment and prognosis.

METHODS: One case of primary atypical fibrous xanthoma of the esophagus treated at Fuzhou General Hospital of Nanjing Military Command of Chinese PLA was analyzed in this study. The diagnosis, treatment and follow-up data as well as histopathological and immunohistochemistry data for the disease were analyzed to reveal the clinicopathologic characteristics of the disease.

RESULTS: The tumor was located under the squamous epithelium of the upper esophagus, with a clear boundary. Histopathological analysis showed that the tumor was composed of cells of spindle, polygonal and irregular shape, collagen fibers, and esophageal glands. The tumor cells consisted of mononuclear, binuclear and polynuclear giant cells that shared some similar morphological characteristics. Mononuclear, binuclear and polynuclear giant cells could be detected in the transitional area. Some areas revealed pathological mitosis (< 2/50 HPF). Immunohistochemistry analysis showed that the tumor cells were strongly positive for CD68, CD163, S-100, and vimentin, weakly positive for α-SMA, h-caldesmon, and Ki-67 (proliferation index: ~8%), but negative of CKpan, EMA, CK (L), CK (H), F8, CD34, CD117, Dog-1, actin, desmin, CD10, and CD99.

CONCLUSION: Primary atypical fibrous xanthoma of the esophagus is an extremely rare mesenchymal tumor with benign behavior and good prognosis. A differential diagnosis should be made among atypical fibrous xanthoma of the esophagus, esophageal sarcomatoid carcinoma, carcinoma-sarcoma, leiomyoma, gastrointestinal stromal tumor, and malignant fibrous histiocytoma.