Myxofibrosarcoma mimicking cutaneous myxoma

Multiple cutaneous myxofibrosarcoma on the right arm: Clinicopathological features and differential diagnosis

The clinical presentations and pathological features of low-grade myxofibrosarcoma can be misleading, frequently resulting in diagnostic errors. An accurate diagnosis requires the application of immunohistochemistry techniques and the discerning diagnostic acumen of experienced pathologists. A 62-year-old male patient visited our outpatient clinic with multiple painful and rapidly enlarging subcutaneous nodules on his right forearm. Initially, the condition was misdiagnosed as multiple lipomas. The final pathology revealed characteristics consistent with low-grade myxofibrosarcoma.

Immediate and Delayed Hypersensitivity Reactions to Antibiotics: Aminoglycosides, Clindamycin, Linezolid, and Metronidazole

Hypersensitivity reactions including IgE-mediated and delayed cell-mediated reactions to aminoglycosides, clindamycin, linezolid, and metronidazole are rare. For aminoglycosides, allergic contact dermatitis is the most frequent reaction for which patch testing can be a useful step in evaluation. For clindamycin, delayed maculopapular exanthems are the most common reactions. There are case reports of clindamycin associated with drug rash with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP), acute febrile neutrophilic dermatosis, and symmetrical drug-related intertriginous and flexural exanthema (SDRIFE). For linezolid, cases of hypersensitivity were exceedingly rare and included urticaria, angioedema, anaphylaxis, delayed rashes, and DRESS. For metronidazole, only rare cases were found across a broad spectrum of reactions including allergic contact dermatitis, fixed drug eruption, angioedema, anaphylaxis, serum sickness-like reaction, SJS/TEN, AGEP, SDRIFE, and a possible case of DRESS. IgE-mediated reactions and anaphylaxis to these types of antibiotics are uncommon, and reports of skin testing concentrations and desensitization protocols are largely limited to case reports and series. Non-irritating skin testing concentrations have been reported for gentamycin, tobramycin, and clindamycin. Published desensitization protocols for intravenous and inhaled tobramycin, oral clindamycin, intravenous linezolid, and oral and intravenous metronidazole have also been reported and are reviewed.

Rare, risky, recurrent: An enigmatic cutaneous polyp

Myxofibrosarcomas (MFSs) are sarcomas most commonly seen in older patients. These are tumors of deep soft tissue seen in subcutaneous tissue and deep fascia, with frequent muscle involvement. These sarcomas are notorious for recurrences and progression to a higher grade with notable metastatic potential. They are very often under-diagnosed owing to their inherent morphological variability. A case of MFS is presented as a cutaneous, exophytic, polypoidal mass because of its rarity and importance of timely diagnosis, as under-diagnosis may lead to inadequate clearance of tumor, recurrences, metastases and increased mortality.

CD34-positive superficial myxofibrosarcoma: a potential diagnostic pitfall

BACKGROUND

Myxofibrosarcoma (MFS) arises most commonly in the proximal extremities of the elderly, where it may involve subcutaneous and dermal tissues and masquerade as benign entities in limited biopsy samples. We encountered such a case, in which positivity for CD34 and morphologic features were initially wrongly interpreted as a 'low-fat/fat-free' spindle cell/pleomorphic lipoma. Case series have not assessed prevalence of CD34 reactivity among cutaneous examples of MFS.

METHODS

We performed a systematic review of our institution's experience, selecting from among unequivocal MFS resection specimens those superficial cases in which a limited biopsy sample might prove difficult to interpret. These cases were immunostained for CD34 and tabulated for clinicopathologic characteristics.

RESULTS

After review of all MFS diagnoses over 5 years (n = 56), we identified a study group of superficial MFS for comparison to the index case (total n = 8). Of these, the index and three additional cases (4 of 8, 50%; 2 low, 2 high grade) demonstrated positive staining for CD34, with diffuse staining of spindled cells including cellular processes. Four additional cases showed no or equivocal/rare staining.

CONCLUSIONS

CD34 positivity should be recognized as prevalent among such cases and should not be inappropriately construed as inveighing against a diagnosis of MFS in favor of benign entities.